This document discusses cold flow analysis of a gas turbine combustor using computational fluid dynamics (CFD). CFD is used to model airflow and fuel injection without reactions to capture mixture formation. The CFD model accounts for moving geometry interactions with fluid dynamics. Cold flow simulations provide useful information on turbulence and mixing to ensure proper combustion conditions. The document outlines objectives of combustor design like satisfactory mixing and stable flow patterns with minimal losses. Numerical analysis and governing equations are presented along with experimental data and graphs showing variation in properties like temperature, pressure, and pattern factor.
This document presents research on developing an emissions prediction capability for use in conceptual aircraft engine design. A physics-based modeling approach was used consisting of 1D flow models of different combustor types, chemical reactor networks representing the combustor flowfields, and regression models. Models were developed for a single annular combustor, rich-quench-lean combustor, and lean-burn combustor. The models were implemented in NPSS and validated against test data. Regression models were also created to rapidly predict emissions for parametric studies of a CFM56-sized engine application. The new capability allows emissions predictions during early engine conceptual design when cycle parameters and architectures are varied.
This document outlines a dissertation proposal to study the effect of geometric parameters on the performance of an annular gas turbine combustion chamber using computational fluid dynamics (CFD). The proposal includes a literature review summarizing previous research on combustion chamber design and CFD modeling. The proposed methodology describes collecting existing dimension data, modeling the combustion chamber geometry, mesh generation, and performing CFD analysis in ANSYS Fluent to optimize performance by varying parameters like swirl angle, nozzle location and size, and hole placement and size.
FLOW DISTRIBUTION NETWORK ANALYSIS FOR DISCHARGE SIDE OF CENTRIFUGAL PUMPijiert bestjournal
A computational fluid dynamics (CFD) analysis has been conducted to f ind the pressure losses for dividing and combining fluid flow through a junction of discharge system. Si mulations are performed for a range of flow ratios and equations are developed for pressure loss coeff icients at junctions. A mathematical model based on successive approximations then would be employed to estim ate the pressure losses. The proposed CFD based strategy can be used for the analysis of all the thr ee pipe branches of some diameter are selected along with equal length so that only the effect of bend angle can be studied. The effect of bend angle,pipe diameter,pipe length,Reynolds number on the resistance coeffi cient is studied. The software used is CATIA for modeling and ANSYS fluent for analysis purpose.
Heat Transfer Analysis of Refrigerant Flow in an Evaporator TubeIJMER
the paper aim is to presenting the heat transfer analysis of refrigerant flow in an evaporator
tube is done. The main objective of this paper is to find the length of the evaporator tube for a pre-defined
refrigerant inlet state such that the refrigerant at the tube outlet is superheated. The problem involves
refrigerant flowing inside a straight, horizontal copper tube over which water is in cross flow. Inlet
condition of the both fluids and evaporator tube detail except its length are specified. here pressure and
enthalpy at discrete points along the tube are calculated by using two-phase frictional pressure drop model.
Predicted values were compared using another different pressure drop model. A computer-code using
Turbo C has been developed for performing the entire calculation
Numerical study of heat transfer in pulsating turbulent air flowMohamed Fadl
A numerical investigation of heat transfer
characteristics of pulsating turbulent flow in a circular
tube is carried out. The flow is thermally and
hydrodynamically fully developed and the tube wall is
subjected to a uniform heat flux. The flow inlet to the
pipe consists of fixed component and pulsating
component that varies sinusoidally with time. The flow
and temperature fields are computed numerically using
computational fluid dynamics (CFD) Fluent code.
Prediction of heat transfer characteristics is performed
over a range of 10 4 ≤ Re ≤ 4x10 4 and 0 ≤ ƒ ≤ 70 are
observed. Results showed little reduction in the mean
time-averaged Nusselt number with respect to that of
steady flow. However, in the fully developed
established region, the local Nusselt number either
increases or decreases over the steady flow-values
depending on the frequency parameter. These noticed
deviations are rather small in magnitude for the
computed parameter ranges. The characteristics of heat
transfer are qualitatively consistent with the available
experimental and numerical predictions.
This document describes using Excel to optimize the thermal design of systems. It provides an example of optimizing the insulation thickness and pipe diameter of an insulated pipe to minimize costs. Excel is able to calculate the total cost as a function of diameter and use its Solver tool to iteratively find the optimal diameter that minimizes cost. This provides an effective way for students to learn thermal design optimization compared to analytical optimization, as it can handle multiple design factors and parameters. The document then presents another example of using this approach to optimize the diameters and insulation thicknesses of two sections of an air conditioning duct to minimize owning costs.
A Review on Comparison between Shell And Tube Heat Exchanger And Helical Coil...ijiert bestjournal
The curved shape of the tube causes the flowing fluid to experience centrifugal force. The
extent of centrifugal force experienced depends on the local axial velocity of the fluid particle
and radius of curvature of the coil. The fluid particles flowing at the core of the pipe have
higher velocities than those flowing near to the pipe wall. Thus the fluid particles flowing
close to the tube wall experience a lower centrifugal force than the fluid particles flowing in
the tube core. This causes the fluid from the core region to be pushed towards the outer wall.
This stream bifurcates at the wall and drives the fluid towards the inner wall along the tube
periphery, causing generation of counter-rotating vortices called secondary flows which
produce additional transport of the fluid over the cross section of the pipe. This additional
convective transport increases heat transfer and the pressure drop when compared to that in a
straight tube.
This document discusses cold flow analysis of a gas turbine combustor using computational fluid dynamics (CFD). CFD is used to model airflow and fuel injection without reactions to capture mixture formation. The CFD model accounts for moving geometry interactions with fluid dynamics. Cold flow simulations provide useful information on turbulence and mixing to ensure proper combustion conditions. The document outlines objectives of combustor design like satisfactory mixing and stable flow patterns with minimal losses. Numerical analysis and governing equations are presented along with experimental data and graphs showing variation in properties like temperature, pressure, and pattern factor.
This document presents research on developing an emissions prediction capability for use in conceptual aircraft engine design. A physics-based modeling approach was used consisting of 1D flow models of different combustor types, chemical reactor networks representing the combustor flowfields, and regression models. Models were developed for a single annular combustor, rich-quench-lean combustor, and lean-burn combustor. The models were implemented in NPSS and validated against test data. Regression models were also created to rapidly predict emissions for parametric studies of a CFM56-sized engine application. The new capability allows emissions predictions during early engine conceptual design when cycle parameters and architectures are varied.
This document outlines a dissertation proposal to study the effect of geometric parameters on the performance of an annular gas turbine combustion chamber using computational fluid dynamics (CFD). The proposal includes a literature review summarizing previous research on combustion chamber design and CFD modeling. The proposed methodology describes collecting existing dimension data, modeling the combustion chamber geometry, mesh generation, and performing CFD analysis in ANSYS Fluent to optimize performance by varying parameters like swirl angle, nozzle location and size, and hole placement and size.
FLOW DISTRIBUTION NETWORK ANALYSIS FOR DISCHARGE SIDE OF CENTRIFUGAL PUMPijiert bestjournal
A computational fluid dynamics (CFD) analysis has been conducted to f ind the pressure losses for dividing and combining fluid flow through a junction of discharge system. Si mulations are performed for a range of flow ratios and equations are developed for pressure loss coeff icients at junctions. A mathematical model based on successive approximations then would be employed to estim ate the pressure losses. The proposed CFD based strategy can be used for the analysis of all the thr ee pipe branches of some diameter are selected along with equal length so that only the effect of bend angle can be studied. The effect of bend angle,pipe diameter,pipe length,Reynolds number on the resistance coeffi cient is studied. The software used is CATIA for modeling and ANSYS fluent for analysis purpose.
Heat Transfer Analysis of Refrigerant Flow in an Evaporator TubeIJMER
the paper aim is to presenting the heat transfer analysis of refrigerant flow in an evaporator
tube is done. The main objective of this paper is to find the length of the evaporator tube for a pre-defined
refrigerant inlet state such that the refrigerant at the tube outlet is superheated. The problem involves
refrigerant flowing inside a straight, horizontal copper tube over which water is in cross flow. Inlet
condition of the both fluids and evaporator tube detail except its length are specified. here pressure and
enthalpy at discrete points along the tube are calculated by using two-phase frictional pressure drop model.
Predicted values were compared using another different pressure drop model. A computer-code using
Turbo C has been developed for performing the entire calculation
Numerical study of heat transfer in pulsating turbulent air flowMohamed Fadl
A numerical investigation of heat transfer
characteristics of pulsating turbulent flow in a circular
tube is carried out. The flow is thermally and
hydrodynamically fully developed and the tube wall is
subjected to a uniform heat flux. The flow inlet to the
pipe consists of fixed component and pulsating
component that varies sinusoidally with time. The flow
and temperature fields are computed numerically using
computational fluid dynamics (CFD) Fluent code.
Prediction of heat transfer characteristics is performed
over a range of 10 4 ≤ Re ≤ 4x10 4 and 0 ≤ ƒ ≤ 70 are
observed. Results showed little reduction in the mean
time-averaged Nusselt number with respect to that of
steady flow. However, in the fully developed
established region, the local Nusselt number either
increases or decreases over the steady flow-values
depending on the frequency parameter. These noticed
deviations are rather small in magnitude for the
computed parameter ranges. The characteristics of heat
transfer are qualitatively consistent with the available
experimental and numerical predictions.
This document describes using Excel to optimize the thermal design of systems. It provides an example of optimizing the insulation thickness and pipe diameter of an insulated pipe to minimize costs. Excel is able to calculate the total cost as a function of diameter and use its Solver tool to iteratively find the optimal diameter that minimizes cost. This provides an effective way for students to learn thermal design optimization compared to analytical optimization, as it can handle multiple design factors and parameters. The document then presents another example of using this approach to optimize the diameters and insulation thicknesses of two sections of an air conditioning duct to minimize owning costs.
A Review on Comparison between Shell And Tube Heat Exchanger And Helical Coil...ijiert bestjournal
The curved shape of the tube causes the flowing fluid to experience centrifugal force. The
extent of centrifugal force experienced depends on the local axial velocity of the fluid particle
and radius of curvature of the coil. The fluid particles flowing at the core of the pipe have
higher velocities than those flowing near to the pipe wall. Thus the fluid particles flowing
close to the tube wall experience a lower centrifugal force than the fluid particles flowing in
the tube core. This causes the fluid from the core region to be pushed towards the outer wall.
This stream bifurcates at the wall and drives the fluid towards the inner wall along the tube
periphery, causing generation of counter-rotating vortices called secondary flows which
produce additional transport of the fluid over the cross section of the pipe. This additional
convective transport increases heat transfer and the pressure drop when compared to that in a
straight tube.
Presentation on Computational fluid dynamic smulation and benchmarking a dess...kush verma
Check out one of the first of its kind simulation work on Ranque Hilsch Vortex Tube. The authors have done exhaustive work including simulation (from multiple application software Ansys and OpenFOAM), programming (C++ and excel) and plots (excel and qtiplot) along with experimental work. They have simplified and standardized the process to an extend that it would even be helpful for a beginner in this field.
This document describes a CFD analysis of fluid flow through tube banks in heat recovery steam generators (HRSGs). The authors developed a new procedure to define porous medium parameters like loss coefficients starting from 3D simulations of flow through tube banks. Both finned and bare tube banks were considered. The analysis was performed using the commercial CFD code Fluent to simulate flow through a single tube row and investigate the effects of Reynolds number, inlet yaw angle, and inlet pitch angle on pressure drop and outlet flow angles. Results were compared to experimental data for a real fired HRSG to validate the proposed porous media modeling approach.
Techniques of heat transfer enhancement and their application chapter 6ssusercf6d0e
This document discusses different types of externally finned tubes used in heat exchangers. It describes plain plate fins attached to round tubes, as well as enhanced fin geometries like wavy and interrupted fins. The effects of fin spacing and geometry on heat transfer and friction are examined. Reynolds number is defined based on both tube diameter and hydraulic diameter, and it is noted that tube diameter may be a better characteristic length for finned tubes. Friction factor definitions are also discussed.
IJREI_Thermodynamic study of R134a in Vapour Compression Refrigeration System...Husain Mehdi
Thermodynamic analysis of an ideal vapour compression refrigeration system is done using refrigerants R134a.This Energy-Exergy analysis is carried out by developed mathematical model. Various parameters are numerically computed are first law efficiency in terms of coefficient of performance (COP) of the system both ideal case and actual experimental and exergetic efficiency and exergy destruction ratio have been computed . The eco-friendly R134a refrigerant gives lower COP than R22. Comparing with R22, R134a takes more compressor power and second law efficiency (exergetic efficiency) of VCRS is also lower than using R22. Due to higher GWP and ODP of R22, R134a can be used for domestic / commercial and industrial applications.
This document summarizes a study that used computational fluid dynamics (CFD) to analyze heat transfer and flow characteristics in a solar air heater duct with ribbed surfaces. CFD simulations were performed for ducts with different rib configurations and Reynolds numbers. It was found that roughening the duct surface increased heat transfer but also increased friction losses. An optimal rib design was identified that provided maximum heat transfer enhancement with minimum pressure drop. Turbulence kinetic energy and intensity contours helped explain the increased turbulence near ribs that augmented heat transfer.
Fundamental Aspects of Droplet Combustion ModellingIJERA Editor
This document summarizes research on modeling liquid droplet combustion. It first describes developing a model that solves transient energy and species equations to simulate an isolated, spherically symmetric single-component droplet burning over time. Results show the flame diameter initially increases then decreases and the flame to droplet ratio changes throughout burning unlike quasi-steady models. The model is extended to include forced convection effects. Emission profiles for species like CO, CO2, H2O and NO are also determined. Finally, the document discusses modeling multicomponent droplets, high-pressure combustion, and the governing equations involved.
Application of Parabolic Trough Collectorfor Reduction of Pressure Drop in Oi...IJMER
Pipelines are the least expensive and most effective method for the oil transportation.
Due to high viscosity of crude oil, the pressure drop and pumping power requirements are very high.
So it is necessary to bring down the viscosity of crude oil. Heated pipelines are used reduce the oil
viscosity by increasing the oil temperature. Electrical heating and direct flame heating are the common
method used for heating the oil pipeline. In this work, a new application of Parabolic Trough Collector
in the field of oil pipeline transport is introduced for reducing pressure drop in oil pipelines. Oil
pipeline is heated by applying concentrated solar radiation on the pipe surface using a Parabolic
Trough Collector in which the oil pipeline acts as the absorber pipe. 3-D steady state analysis is
carried out on a heated oil pipeline using commercial CFD software package ANSYS Fluent 14.5. In
this work an effort is made to investigate the effect of concentrated solar radiation for reducing
pressure drop in the oil pipeline. The results from the numerical analysis shows that the pressure drop
in oil pipeline is get reduced by heating the pipe line using concentrated solar radiation. From this
work, the application of PTC in oil pipeline transportation is justified.
Numerical analysis of heat transfer in refrigerant flow through a condenser tubeeSAT Journals
Abstract In this thesis, heat transfer analysis of refrigerant flow in a condenser tube has been done. The main objective of this thesis is to find the length of the condenser tube for a pre-defined refrigerant inlet state such that the refrigerant at the tube outlet is saturated liquid or sub cooled liquid. The inlet refrigerant condition is saturated vapor. The problem involves refrigerant flowing inside a straight, horizontal copper tube over which air is in cross flow. Inlet condition of the both fluids and condenser tube detail except its length are specified. Here, changing pressure at discrete points along the tube is calculated by using two-phase frictional pressure drop and momentum equation mode. The heat transfer calculation has done by using condensation heat transfer correlations and simple heat transfer equations. The inside heat transfer coefficient calculated by using two phase heat transfer coefficient correlation. The unknown length of condenser tube has discrete many numbers of small elements. Each and every element has a calculations based on the pressure drop as well as heat transfer based on those correlation and every element calculated properties of refrigerant values has to check its states. At end of the iteration, a last element has reached saturated liquid condition of refrigerant and stops the entire calculation. So the length of condenser tube has been calculated by number of iteration and number of nodes with its distance. Predicted values were compared using another condensation heat transfer correlations. A computer-code using Turbo C has been developed for performing the entire calculation. Keywords: Heat transfer, Refrigeration, Multi phase flow, condenser flow, Tube length
Numerical analysis of heat transfer in refrigerant flow through a condenser tubeeSAT Publishing House
The document describes a numerical analysis of heat transfer in refrigerant flow through a condenser tube. The analysis calculates the length of the condenser tube needed such that the refrigerant exits in a saturated liquid or subcooled liquid state, given inlet conditions. It does this by discretizing the tube into nodes and calculating pressure changes and enthalpy changes between nodes using heat transfer and pressure drop correlations. Input parameters like refrigerant properties, mass flow rates, and tube geometry are specified. Results show the required tube length increases as the inner tube diameter decreases due to increased thermal resistance.
The document presents a computational tool and methodology for simulating compact tube bundle heat exchangers used in recuperated gas turbine engines. Computational fluid dynamics analyses were performed on an oval tube bundle heat exchanger to derive resistance tensors for modeling the heat exchanger as a porous medium. The porous media model was validated against experimental hot gas channel and isothermal flow test data, showing acceptable agreement between calculated and measured velocity profiles and less than 10% deviation in pressure drop. While cold side heat transfer correlations predicted results reasonably well, hot gas calculations overpredicted heat transfer likely due to assumptions about flow regime.
technoloTwo dimensional numerical simulation of the combined heat transfer in...ijmech
A numerical investigation was conducted to analyze the flow field and heat transfer characteristics in a vertical channel withradiation and blowing from the wall. Hydrodynamic behaviour and heat transfer results are obtained by the solution of the complete Navier–Stokesand energy equations using a control volume finite element method. Turbulent flow with "Low Reynolds Spalart-Allmaras Turbulence Model" and radiation with "Discrete Transfer Radiation Method" had been modeled. In order to have a complete survey, this article has a wide range of study in different domains including velocity profiles at different locations, turbulent viscosity, shear stress, suctioned mass flow rate in different magnitude of the input
Rayleigh number, blowing Reynoldsnumber, radiation parameter, Prandtl number, the ratio of length to width and also ratio of opening thickness to width of the channel. In addition, effects of variation in any of the above non-dimensional numbers on parameters of the flow are clearly illustrated. At the end resultants had been compared with experimental data which demonstrated that in the present study, results have a great accuracy, relative errors are very small and the curve portraits are in a great
agreement with real experiments.
REVIEW OF FLOW DISTRIBUTION NETWORK ANALYSIS FOR DISCHARGE SIDE OF CENTRIFUGA...ijiert bestjournal
A computational fluid dynamics (CFD) analysis has been conducted to find the pressure losses for dividing and combining fluid flow through a junction of discharge system. Simulations are performed for a range of flow ratios and equations are developed for pressure loss coefficients at junctions. A mathematical model based on s uccessive approximations then would be employed to estimate the pressure losses. The proposed CFD based strategy can be used for the analysis of all the three pipe branches of s ome diameter are selected along with equal length so that only the effect of bend angle can be st udied. The effect of bend angle,pipe diameter,pipe length,reynolds number on the resistan ce coefficient is studied. The software used is CATIA for modeling and ANSYS fluent for analysis purpose.
Accounting SDR Fluctuations to Non-Premixed Turbulent Combustion for Better P...IJERA Editor
1) The document discusses accounting for scalar dissipation rate fluctuations (SDRF) in computational fluid dynamic (CFD) modeling of in-cylinder combustion processes in internal combustion engines.
2) It aims to improve predictions by developing a user defined function to include SDRF in the existing CFD code FLUENT.
3) Results comparing simulations with and without SDRF show better agreement with experimental data when including SDRF, with errors in peak pressure and temperature predictions reduced from 4.4% to 2.6% and temperatures more accurately predicted.
Thermohydraulic Performance of a Series of In-Line Noncircular Ducts in a Par...Carnegie Mellon University
Heat transfer and fluid flow characteristics for two-dimensional laminar flow at low Reynolds number for five in-line ducts of
various nonconventional cross-sections in a parallel plate channel are studied in this paper.The governing equations were solved
using finite-volumemethod.CommercialCFDsoftware,ANSYS Fluent 14.5,was used to solve this problem.Atotal of three different
nonconventional, noncircular cross-section ducts and their characteristics are compared with those of circular cross-section ducts.
Shape-2 ducts offered minimum flow resistance and maximum heat transfer rate most of the time. Shape-3 ducts at Re < 100 and Shape-2 ducts at Re > 100 can be considered to give out the optimum results.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document discusses air transient cooling characteristics in the entry regions of ducts with non-circular cross sections. It presents correlations and equations to calculate the hydrodynamic and thermal entrance lengths for triangular, rectangular, circular and square ducts. It also provides equations for the local Nusselt number and convective heat transfer coefficient in the combined entry region where the flow is both thermally and hydrodynamically developing. The analysis considers the transient heat transfer in the duct entry regions using temperature-dependent air properties and numerical modeling. The results indicate that the triangular duct enhances heat transfer the most compared to the other cross section ducts.
IRJET- Thermal and Fluid Flow Analysis of a Heat Exchanger: “A Comprehensive ...IRJET Journal
This document provides a comprehensive literature review and analysis of thermal and fluid flow performance in heat exchangers. It discusses several types of heat exchangers and techniques used to enhance heat transfer, such as surface textures, channel designs, and nanofluids. The document reviews experimental, numerical, and computational studies on fluid flow characteristics and heat transfer for different heat exchanger configurations and applications. It also provides governing equations for fluid flow and heat transfer analysis and compares experimental results to analytical predictions using correlations.
An experimental study on kerosene based pulse detonation engineIAEME Publication
This document summarizes an experimental study on a kerosene-based pulse detonation engine. The study tested three equivalence ratios of kerosene and air mixtures. Pressure measurements at different locations along the detonation tube are presented and compared to theoretical Chapman-Jouguet detonation pressures from a NASA chemical equilibrium program. For equivalence ratios of 1.0 and 1.14, the pressure measurements indicate a deflagration to detonation transition occurred before the second measurement location, matching detonation pressures. This confirms stable detonation was achieved in the pulse detonation engine setup.
Numerical Simulation of Flow in a Solid Rocket Motor: Combustion Coupled Pres...inventionjournals
Acomputational study is performed for the simulation of reactive fluid flow in a solid rocket motor chamber with pressure dependent propellant burning surface regression. The model geometry consists of a 2D end burning lab-scale motor. Complete conservation equations of mass, momentum, energy and species are solved with finite rate chemistry. The pressure dependent regressive boundary in the combustion chamber is treated by use of remeshing techniques. Hydrogen and propane combustion processes are examined. Time dependent pressure and burning rate variations are illustrated comprehensively. Temperature and species mass fraction variations are given within the flame zone. Temperature, velocity and density distributions are compared for both constant burning rate and pressure dependent burning rate simulations.
This document summarizes several studies on fluid flow and heat transfer using the lattice Boltzmann method (LBM). It discusses LBM applications to natural convection problems including differentially heated cavities, partially heated cavities, and open cavities. It also applies LBM to magnetohydrodynamic convection and forced convection past square and rectangular cylinders. The document provides details on the governing parameters and objectives of each problem considered in the thesis.
O documento discute as políticas habitacionais em Natal, RN desde o século 19. Analisa como esses projetos frequentemente tinham um caráter segregacionista e como isso se reproduziu em Natal. Também contextualiza os principais projetos habitacionais da cidade dentro do quadro nacional e analisa tendências para entender a sociedade natalense ao longo do tempo.
This document discusses using wind and solar energy for vehicles. It describes how small fans and solar panels can be installed on vehicles to generate electricity from wind and solar power. This electricity can be stored in batteries and used for lights, charging phones, and other purposes. Using wind and solar energy for vehicles provides benefits like reduced fuel consumption, lower emissions, and potential for off-grid power applications. The document also outlines some challenges like higher costs and limited driving range without sunlight. Overall, harvesting wind and solar energy shows promise as an alternative energy source for powering certain vehicle functions and applications.
Presentation on Computational fluid dynamic smulation and benchmarking a dess...kush verma
Check out one of the first of its kind simulation work on Ranque Hilsch Vortex Tube. The authors have done exhaustive work including simulation (from multiple application software Ansys and OpenFOAM), programming (C++ and excel) and plots (excel and qtiplot) along with experimental work. They have simplified and standardized the process to an extend that it would even be helpful for a beginner in this field.
This document describes a CFD analysis of fluid flow through tube banks in heat recovery steam generators (HRSGs). The authors developed a new procedure to define porous medium parameters like loss coefficients starting from 3D simulations of flow through tube banks. Both finned and bare tube banks were considered. The analysis was performed using the commercial CFD code Fluent to simulate flow through a single tube row and investigate the effects of Reynolds number, inlet yaw angle, and inlet pitch angle on pressure drop and outlet flow angles. Results were compared to experimental data for a real fired HRSG to validate the proposed porous media modeling approach.
Techniques of heat transfer enhancement and their application chapter 6ssusercf6d0e
This document discusses different types of externally finned tubes used in heat exchangers. It describes plain plate fins attached to round tubes, as well as enhanced fin geometries like wavy and interrupted fins. The effects of fin spacing and geometry on heat transfer and friction are examined. Reynolds number is defined based on both tube diameter and hydraulic diameter, and it is noted that tube diameter may be a better characteristic length for finned tubes. Friction factor definitions are also discussed.
IJREI_Thermodynamic study of R134a in Vapour Compression Refrigeration System...Husain Mehdi
Thermodynamic analysis of an ideal vapour compression refrigeration system is done using refrigerants R134a.This Energy-Exergy analysis is carried out by developed mathematical model. Various parameters are numerically computed are first law efficiency in terms of coefficient of performance (COP) of the system both ideal case and actual experimental and exergetic efficiency and exergy destruction ratio have been computed . The eco-friendly R134a refrigerant gives lower COP than R22. Comparing with R22, R134a takes more compressor power and second law efficiency (exergetic efficiency) of VCRS is also lower than using R22. Due to higher GWP and ODP of R22, R134a can be used for domestic / commercial and industrial applications.
This document summarizes a study that used computational fluid dynamics (CFD) to analyze heat transfer and flow characteristics in a solar air heater duct with ribbed surfaces. CFD simulations were performed for ducts with different rib configurations and Reynolds numbers. It was found that roughening the duct surface increased heat transfer but also increased friction losses. An optimal rib design was identified that provided maximum heat transfer enhancement with minimum pressure drop. Turbulence kinetic energy and intensity contours helped explain the increased turbulence near ribs that augmented heat transfer.
Fundamental Aspects of Droplet Combustion ModellingIJERA Editor
This document summarizes research on modeling liquid droplet combustion. It first describes developing a model that solves transient energy and species equations to simulate an isolated, spherically symmetric single-component droplet burning over time. Results show the flame diameter initially increases then decreases and the flame to droplet ratio changes throughout burning unlike quasi-steady models. The model is extended to include forced convection effects. Emission profiles for species like CO, CO2, H2O and NO are also determined. Finally, the document discusses modeling multicomponent droplets, high-pressure combustion, and the governing equations involved.
Application of Parabolic Trough Collectorfor Reduction of Pressure Drop in Oi...IJMER
Pipelines are the least expensive and most effective method for the oil transportation.
Due to high viscosity of crude oil, the pressure drop and pumping power requirements are very high.
So it is necessary to bring down the viscosity of crude oil. Heated pipelines are used reduce the oil
viscosity by increasing the oil temperature. Electrical heating and direct flame heating are the common
method used for heating the oil pipeline. In this work, a new application of Parabolic Trough Collector
in the field of oil pipeline transport is introduced for reducing pressure drop in oil pipelines. Oil
pipeline is heated by applying concentrated solar radiation on the pipe surface using a Parabolic
Trough Collector in which the oil pipeline acts as the absorber pipe. 3-D steady state analysis is
carried out on a heated oil pipeline using commercial CFD software package ANSYS Fluent 14.5. In
this work an effort is made to investigate the effect of concentrated solar radiation for reducing
pressure drop in the oil pipeline. The results from the numerical analysis shows that the pressure drop
in oil pipeline is get reduced by heating the pipe line using concentrated solar radiation. From this
work, the application of PTC in oil pipeline transportation is justified.
Numerical analysis of heat transfer in refrigerant flow through a condenser tubeeSAT Journals
Abstract In this thesis, heat transfer analysis of refrigerant flow in a condenser tube has been done. The main objective of this thesis is to find the length of the condenser tube for a pre-defined refrigerant inlet state such that the refrigerant at the tube outlet is saturated liquid or sub cooled liquid. The inlet refrigerant condition is saturated vapor. The problem involves refrigerant flowing inside a straight, horizontal copper tube over which air is in cross flow. Inlet condition of the both fluids and condenser tube detail except its length are specified. Here, changing pressure at discrete points along the tube is calculated by using two-phase frictional pressure drop and momentum equation mode. The heat transfer calculation has done by using condensation heat transfer correlations and simple heat transfer equations. The inside heat transfer coefficient calculated by using two phase heat transfer coefficient correlation. The unknown length of condenser tube has discrete many numbers of small elements. Each and every element has a calculations based on the pressure drop as well as heat transfer based on those correlation and every element calculated properties of refrigerant values has to check its states. At end of the iteration, a last element has reached saturated liquid condition of refrigerant and stops the entire calculation. So the length of condenser tube has been calculated by number of iteration and number of nodes with its distance. Predicted values were compared using another condensation heat transfer correlations. A computer-code using Turbo C has been developed for performing the entire calculation. Keywords: Heat transfer, Refrigeration, Multi phase flow, condenser flow, Tube length
Numerical analysis of heat transfer in refrigerant flow through a condenser tubeeSAT Publishing House
The document describes a numerical analysis of heat transfer in refrigerant flow through a condenser tube. The analysis calculates the length of the condenser tube needed such that the refrigerant exits in a saturated liquid or subcooled liquid state, given inlet conditions. It does this by discretizing the tube into nodes and calculating pressure changes and enthalpy changes between nodes using heat transfer and pressure drop correlations. Input parameters like refrigerant properties, mass flow rates, and tube geometry are specified. Results show the required tube length increases as the inner tube diameter decreases due to increased thermal resistance.
The document presents a computational tool and methodology for simulating compact tube bundle heat exchangers used in recuperated gas turbine engines. Computational fluid dynamics analyses were performed on an oval tube bundle heat exchanger to derive resistance tensors for modeling the heat exchanger as a porous medium. The porous media model was validated against experimental hot gas channel and isothermal flow test data, showing acceptable agreement between calculated and measured velocity profiles and less than 10% deviation in pressure drop. While cold side heat transfer correlations predicted results reasonably well, hot gas calculations overpredicted heat transfer likely due to assumptions about flow regime.
technoloTwo dimensional numerical simulation of the combined heat transfer in...ijmech
A numerical investigation was conducted to analyze the flow field and heat transfer characteristics in a vertical channel withradiation and blowing from the wall. Hydrodynamic behaviour and heat transfer results are obtained by the solution of the complete Navier–Stokesand energy equations using a control volume finite element method. Turbulent flow with "Low Reynolds Spalart-Allmaras Turbulence Model" and radiation with "Discrete Transfer Radiation Method" had been modeled. In order to have a complete survey, this article has a wide range of study in different domains including velocity profiles at different locations, turbulent viscosity, shear stress, suctioned mass flow rate in different magnitude of the input
Rayleigh number, blowing Reynoldsnumber, radiation parameter, Prandtl number, the ratio of length to width and also ratio of opening thickness to width of the channel. In addition, effects of variation in any of the above non-dimensional numbers on parameters of the flow are clearly illustrated. At the end resultants had been compared with experimental data which demonstrated that in the present study, results have a great accuracy, relative errors are very small and the curve portraits are in a great
agreement with real experiments.
REVIEW OF FLOW DISTRIBUTION NETWORK ANALYSIS FOR DISCHARGE SIDE OF CENTRIFUGA...ijiert bestjournal
A computational fluid dynamics (CFD) analysis has been conducted to find the pressure losses for dividing and combining fluid flow through a junction of discharge system. Simulations are performed for a range of flow ratios and equations are developed for pressure loss coefficients at junctions. A mathematical model based on s uccessive approximations then would be employed to estimate the pressure losses. The proposed CFD based strategy can be used for the analysis of all the three pipe branches of s ome diameter are selected along with equal length so that only the effect of bend angle can be st udied. The effect of bend angle,pipe diameter,pipe length,reynolds number on the resistan ce coefficient is studied. The software used is CATIA for modeling and ANSYS fluent for analysis purpose.
Accounting SDR Fluctuations to Non-Premixed Turbulent Combustion for Better P...IJERA Editor
1) The document discusses accounting for scalar dissipation rate fluctuations (SDRF) in computational fluid dynamic (CFD) modeling of in-cylinder combustion processes in internal combustion engines.
2) It aims to improve predictions by developing a user defined function to include SDRF in the existing CFD code FLUENT.
3) Results comparing simulations with and without SDRF show better agreement with experimental data when including SDRF, with errors in peak pressure and temperature predictions reduced from 4.4% to 2.6% and temperatures more accurately predicted.
Thermohydraulic Performance of a Series of In-Line Noncircular Ducts in a Par...Carnegie Mellon University
Heat transfer and fluid flow characteristics for two-dimensional laminar flow at low Reynolds number for five in-line ducts of
various nonconventional cross-sections in a parallel plate channel are studied in this paper.The governing equations were solved
using finite-volumemethod.CommercialCFDsoftware,ANSYS Fluent 14.5,was used to solve this problem.Atotal of three different
nonconventional, noncircular cross-section ducts and their characteristics are compared with those of circular cross-section ducts.
Shape-2 ducts offered minimum flow resistance and maximum heat transfer rate most of the time. Shape-3 ducts at Re < 100 and Shape-2 ducts at Re > 100 can be considered to give out the optimum results.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document discusses air transient cooling characteristics in the entry regions of ducts with non-circular cross sections. It presents correlations and equations to calculate the hydrodynamic and thermal entrance lengths for triangular, rectangular, circular and square ducts. It also provides equations for the local Nusselt number and convective heat transfer coefficient in the combined entry region where the flow is both thermally and hydrodynamically developing. The analysis considers the transient heat transfer in the duct entry regions using temperature-dependent air properties and numerical modeling. The results indicate that the triangular duct enhances heat transfer the most compared to the other cross section ducts.
IRJET- Thermal and Fluid Flow Analysis of a Heat Exchanger: “A Comprehensive ...IRJET Journal
This document provides a comprehensive literature review and analysis of thermal and fluid flow performance in heat exchangers. It discusses several types of heat exchangers and techniques used to enhance heat transfer, such as surface textures, channel designs, and nanofluids. The document reviews experimental, numerical, and computational studies on fluid flow characteristics and heat transfer for different heat exchanger configurations and applications. It also provides governing equations for fluid flow and heat transfer analysis and compares experimental results to analytical predictions using correlations.
An experimental study on kerosene based pulse detonation engineIAEME Publication
This document summarizes an experimental study on a kerosene-based pulse detonation engine. The study tested three equivalence ratios of kerosene and air mixtures. Pressure measurements at different locations along the detonation tube are presented and compared to theoretical Chapman-Jouguet detonation pressures from a NASA chemical equilibrium program. For equivalence ratios of 1.0 and 1.14, the pressure measurements indicate a deflagration to detonation transition occurred before the second measurement location, matching detonation pressures. This confirms stable detonation was achieved in the pulse detonation engine setup.
Numerical Simulation of Flow in a Solid Rocket Motor: Combustion Coupled Pres...inventionjournals
Acomputational study is performed for the simulation of reactive fluid flow in a solid rocket motor chamber with pressure dependent propellant burning surface regression. The model geometry consists of a 2D end burning lab-scale motor. Complete conservation equations of mass, momentum, energy and species are solved with finite rate chemistry. The pressure dependent regressive boundary in the combustion chamber is treated by use of remeshing techniques. Hydrogen and propane combustion processes are examined. Time dependent pressure and burning rate variations are illustrated comprehensively. Temperature and species mass fraction variations are given within the flame zone. Temperature, velocity and density distributions are compared for both constant burning rate and pressure dependent burning rate simulations.
This document summarizes several studies on fluid flow and heat transfer using the lattice Boltzmann method (LBM). It discusses LBM applications to natural convection problems including differentially heated cavities, partially heated cavities, and open cavities. It also applies LBM to magnetohydrodynamic convection and forced convection past square and rectangular cylinders. The document provides details on the governing parameters and objectives of each problem considered in the thesis.
O documento discute as políticas habitacionais em Natal, RN desde o século 19. Analisa como esses projetos frequentemente tinham um caráter segregacionista e como isso se reproduziu em Natal. Também contextualiza os principais projetos habitacionais da cidade dentro do quadro nacional e analisa tendências para entender a sociedade natalense ao longo do tempo.
This document discusses using wind and solar energy for vehicles. It describes how small fans and solar panels can be installed on vehicles to generate electricity from wind and solar power. This electricity can be stored in batteries and used for lights, charging phones, and other purposes. Using wind and solar energy for vehicles provides benefits like reduced fuel consumption, lower emissions, and potential for off-grid power applications. The document also outlines some challenges like higher costs and limited driving range without sunlight. Overall, harvesting wind and solar energy shows promise as an alternative energy source for powering certain vehicle functions and applications.
Salvador possui um clima quente e úmido com praias famosas, é a cidade com maior população de descendentes africanos no mundo e tem uma rica cultura afro-brasileira. Sua economia é baseada no turismo, atraído por sua arquitetura colonial, cultura e eventos como o Carnaval, movimentando R$600 milhões. Antigamente dependia da exportação de açúcar e cacau.
O documento fornece informações sobre a cidade de Manaus no Amazonas, incluindo sua população, área, clima e vegetação. A cultura local é baseada no povo nativo amazônico e na influência européia. A economia de Manaus se baseia em indústrias, agropecuária e extrativismo da floresta amazônica.
Effect of tip clearance on a centrifugal compressorIAEME Publication
This document summarizes a computational analysis of the effect of tip clearance on a low-speed centrifugal compressor. A centrifugal compressor impeller with three tip clearances (0%, 2%, and 5% of blade height) was examined at five flow coefficients using computational fluid dynamics software. The results found that static and total pressure decreased with increasing tip clearance. Blade loading charts and pressure/velocity contours showed lower pressures and velocities on the blade surfaces with larger tip clearances. In conclusion, tip clearances were found to increase losses in the centrifugal compressor.
This document summarizes an experimental study that uses an artificial neural network (ANN) to predict vibrations and cutting forces during turning operations. Experimental tests were conducted under various cutting conditions on an EN-8 workpiece material. Vibrations were measured with an accelerometer and FFT analyzer, and cutting forces were measured with a dynamometer. The experimental data was then used to train an ANN model in Matlab to predict vibrations and forces based on cutting parameters like spindle speed, feed rate, and depth of cut. The goal was to develop an ANN model that could predict vibrations and forces to avoid tool failure and improve process efficiency, quality, and costs.
The document summarizes research on the design and fabrication of hybrid composite springs. Five different types of springs were created using epoxy, glass fiber, and silk at varying volume fractions. Mechanical tests were conducted to evaluate the springs' performance. Literature on composite leaf springs, natural fiber composites, and fatigue testing of helical springs is also reviewed. The research aims to reduce vehicle weight through replacing traditional steel springs with lighter composite alternatives.
Experimental investigation of waste heat recovery system for domestic refrige...IAEME Publication
This document describes an experimental investigation of a waste heat recovery system for a domestic refrigerator. The system utilizes the waste heat from the refrigerator's condenser, which is typically around 32-43°C, by installing a water tank to recover heat from the compressed refrigerant gas before it enters the condenser via a process called desuperheating. Tests were conducted with the refrigerator operating normally and operating as a refrigerator-water heater. Results found that waste heat recovery from domestic refrigerators is technically feasible and can economically preheat water. The document provides details on the experimental setup, which includes modifications made to a domestic refrigerator to integrate a water tank for desuperheating, and instrumentation used to collect temperature and energy consumption data.
The document promotes the opportunity to become an Arbonne Independent Consultant. It highlights that consultants can earn income through commissions on personal and team product sales, and that success is based on building a team. The compensation plan allows consultants to earn more as they progress through different management levels. The opportunity provides flexibility to work full or part-time and to make a difference by helping others.
This document describes the catalysis of substitution reactions on heterocycles bound to a solid phase. It discusses immobilizing 2,6-dichloropurine on a Rink resin, performing C6-substitution with various amines in high yields, and C2-substitution via palladium-mediated coupling reactions such as Suzuki and amination reactions. It also investigates modifying the polymeric support by treating it with a brominating agent to install bromine complexes on the resin for further substitution chemistries. The reactivity of the bromine complex is explored, finding it performs selective side reactions in dry benzene that are not possible in NMP solvent.
A agência Oxygen Marketing Solutions cria ideias que inspiram crenças duradouras nos consumidores e gera soluções combinando percepção de negócio e alto poder criativo. Ela constrói marcas capazes de seduzir legiões de seguidores por meio de planejamento estratégico de marketing e desenvolvimento de ideias criativas.
Two body abrasive wear behavior of short glass fiber and particulate filled p...IAEME Publication
This document summarizes the results of an investigation into the two-body abrasive wear behavior of different polymethylmethacrylate (PMMA) composites. Three composites were tested: PMMA with polytetrafluoroethylene (PTFE) and short glass fiber (1P); 1P with silicon carbide (SiC) microparticles (2P); and 2P with molybdenum disulfide (MoS2) nanoparticles (3P). Two-body abrasive wear tests were conducted using varying loads, abrasive paper grit sizes, and abrading distances. The results showed that wear loss and specific wear rate increased with grit size and load, and decreased with abrading distance
O documento discute fatores que podem comprometer relacionamentos como incompatibilidade, problemas sexuais e infidelidade. Também aborda como manter a união estável diante de desafios e define que as relações sexuais dentro do casamento devem ter aprovação de Deus, sem pornografia ou segredos que possam causar desconfiança.
PARAMETRIC INVESTIGATIONS ON THE FLOW CHARACTERISTICS OF A CLOSED LOOP PULSAT...IAEME Publication
Pulsating Heat Pipe (PHP) is two phase passive heat transfer device for low temperature applications. Even though it is a simple, flexible and cheap structure, its complex physics has not been fully understood and requires a robust, validated simulation tool. In the present work the basic theoretical model by H.B. Ma et al has been updated with the inclusion of capillary effect in order to characterise the pulsating flow for various refrigerants which could be used in PHPs. The mathematical model is solved using explicit embedded Range-kutta method and the slug displacement and velocity are investigated under various influencing parameters.
This paper addresses the numerical simulation of
helically coiled closed loop pulsating heat pipe which is carried
in ANSYS Fluent. The values of thermal resistance for
constant heat fluxes vs. transient heat fluxes are analyzed.
Phase change visualization after the end of simulation is
carried out to observe the phenomenon in liquid at its
saturation temperature and pressure. Finally, helical heat
pipes are found to have thermal resistance less by 2.7K/W,
0.56 K/W, and 0.227 K/W for 8W, 40W and 80W heat inputs
than circular pipes. Helical heat pipes are found more efficient
than circular heat pipes.
NUMERICAL SIMULATION OF FORCED CONVECTION HEAT TRANSFER ENHANCEMENT BY POROUS...IAEME Publication
Pin fins have a variety of applications in industry due to their excellent heat transfer performance, e.g., in cooling of electronic components, in cooling of gas turbine blades, and
recently, in hot water boilers of central heating systems. The forced convective heat transfer in three dimensional porous pin fin channels is numerically studied using ANSYS Fluent. Geometric modelling is done using Design Modeller and CFD Meshing is carried out using ANSYS Meshing Preprocessor. The effects of Reynolds number (Re), pore density (PPI) and pin fin form are studied in detail.
CFD Investigation of Compact Heat Exchanger Having Different Fins with Nanofl...IRJET Journal
This document summarizes research on using computational fluid dynamics (CFD) to investigate heat transfer in a compact heat exchanger with different fin types and titanium dioxide nanofluid. It discusses past research on various techniques for enhancing heat transfer and reducing pressure losses in heat exchangers. The document then outlines the objectives, methodology, and potential implications of research using CFD and limited experimental data to develop new heat transfer and pressure drop correlations for plain, offset strip, and wavy fins, which are common in applications like cryogenics and aerospace. These new correlations could provide more accurate and broadly applicable insights for heat exchanger design compared to existing correlations.
IRJET-To Investigate the effect of Spinner Geometry on COP of Vortex Tube Ref...IRJET Journal
This document summarizes a research paper that investigates how changing the geometry of the spinner inside a vortex tube affects its coefficient of performance (COP) for refrigeration. The paper describes how a vortex tube works by separating compressed air into hot and cold streams. It then discusses changing the angle of the spinner notches within the vortex tube from 25 to 45 degrees and using computational fluid dynamics (CFD) software to analyze how this affects temperatures and COP. The document reviews previous literature on vortex tube experiments and analysis, and describes the methodology of using CAD software to model different spinner angles and CFD to simulate flow, temperature, and pressure within the vortex tube.
This document summarizes a study that uses computational fluid dynamics (CFD) to analyze the flow and heat transfer characteristics of different elliptical pin fin heat sink configurations. The study aims to examine the effects of elliptical pin fin design parameters on heat sink performance. CFD simulations are conducted using ANSYS Fluent software to compute the thermal resistance, heat transfer coefficient, and surface Nusselt number of plate fin and elliptical pin fin heat sinks. Results show that the elliptical pin fin heat sink has better heat transfer performance than the plate fin heat sink. Simulation results for thermal resistance and pressure drop are validated against experimental data from previous studies.
This document provides a review of the historical development and present state of ejector systems. It discusses several topics related to ejector systems including:
1. Developments in ejector models from early single-phase models to more recent two-phase and computational fluid dynamics (CFD) models.
2. Applications of ejector systems including refrigeration, vacuum systems, and other pumping situations.
3. Research aimed at enhancing the performance of ejector systems, such as combining ejectors with other refrigeration cycles to improve overall system performance.
The review categorizes and summarizes the various modeling approaches and research works related to ejector systems, providing useful guidelines on background, operating principles, and areas where
Heat Transfer & Periodic Flow Analysis of Heat Exchanger by CFD with Nano FluidsIJERA Editor
Many heat transfer applications such as steam generators in a boiler or air cooling coil of an air conditioner, can
be modelled in a bank of tubes containing a fluid flowing at one temperature that is immersed in a second fluid
in a cross flow at different temperature. CFD simulations are a useful tool for understanding flow and heat
transfer principles as well as for modelling these types of geometries. Both the fluids considered in the present
study are CUO Nano fluids, and flow is classified as laminar and steady with Reynolds number between 100-
600.The mass flow rate of the cross flow and diameter has been varied (such as 0.05, 0.1, 0.15, 0.20, 0.25, 0.30
kg/sec and 0.8, 1.0.1.2 &1.4cm) and the models are used to predict the flow and temperature fields that result
from convective heat transfer. Due to symmetry of the tube bank and the periodicity of the flow inherent in the
tube bank geometry, only a portion of the geometry will be modelled and with symmetry applied to the outer
boundaries. The inflow boundary will be redefined as a periodic zone and the outflow boundary is defined as the
shadow. The various static pressures, velocities, and temperatures obtained are reported.
In this present project tubes of different diameters and different mass flow rates are considered to examine the
optimal flow distribution. Further the problem has been subjected to effect of materials used for tubes
manufacturing on heat transfer rate. Materials considered are copper and Nickle Chromium alloys. Results
emphasize the utilization of alloys in place of copper as tube material serves better heat transfer with most
economical way.
Heat Transfer & Periodic Flow Analysis of Heat Exchanger by CFD with Nano FluidsIJERA Editor
Many heat transfer applications such as steam generators in a boiler or air cooling coil of an air conditioner, can
be modelled in a bank of tubes containing a fluid flowing at one temperature that is immersed in a second fluid
in a cross flow at different temperature. CFD simulations are a useful tool for understanding flow and heat
transfer principles as well as for modelling these types of geometries. Both the fluids considered in the present
study are CUO Nano fluids, and flow is classified as laminar and steady with Reynolds number between 100-
600.The mass flow rate of the cross flow and diameter has been varied (such as 0.05, 0.1, 0.15, 0.20, 0.25, 0.30
kg/sec and 0.8, 1.0.1.2 &1.4cm) and the models are used to predict the flow and temperature fields that result
from convective heat transfer. Due to symmetry of the tube bank and the periodicity of the flow inherent in the
tube bank geometry, only a portion of the geometry will be modelled and with symmetry applied to the outer
boundaries. The inflow boundary will be redefined as a periodic zone and the outflow boundary is defined as the
shadow. The various static pressures, velocities, and temperatures obtained are reported.
In this present project tubes of different diameters and different mass flow rates are considered to examine the
optimal flow distribution. Further the problem has been subjected to effect of materials used for tubes
manufacturing on heat transfer rate. Materials considered are copper and Nickle Chromium alloys. Results
emphasize the utilization of alloys in place of copper as tube material serves better heat transfer with most
economical way
Performance prediction of a thermal system using Artificial Neural NetworksIJERD Editor
This document summarizes a study on using artificial neural networks (ANNs) to predict the performance of a condenser system and assess fouling over time. Experiments were conducted on an industrial condenser to collect temperature and flow rate data. An ANN model was developed and trained to predict the overall heat transfer coefficient of the clean condenser system based on the input parameters. The model was then used to calculate the fouling factor by comparing the predicted clean performance to the actual performance measured over time, indicating degradation due to fouling on the heat transfer surfaces. The developed system provides a method to monitor condenser performance and identify when cleaning is needed to improve efficiency.
This document summarizes a numerical simulation study of heat transfer enhancement in a tube fitted with rod helical tape swirl generators. The study uses ANSYS Fluent to model heat transfer and flow characteristics of air flowing inside a circular tube with different tube insert configurations. Results are compared to experimental and analytical calculations from other studies. Enhanced heat transfer is observed with decreasing twist ratio of the helical tape inserts. Heat flux is also found to be more uniform along the tube length with the inserts.
NUMERICAL SIMULATION OF ENHANCEMENT OF HEAT TRANSFER IN A TUBE WITH AND WITHO...IAEME Publication
The heat transfer augmentation techniques are widely utilized in many applications in the heating process to enable reduction in weight and size or increase the performance of heat exchangers. These techniques are classified as active and passive techniques. The active technique required external power such as surface vibration and electric or acoustic fields, whereas the passive techniques required fluid additives, special surface geometries, or swirl/vortex flow devices, that is, twisted tape inserts. Computational heat transfer flow modeling is one of the great challenges in the
classical sciences.
Fuzzy Logic Modeling of Heat Transfer in a double Pipe Heat Exchanger with Wa...ijiert bestjournal
Fuzzy logic is a method which can be used to model the experiments,and it has been introduced for the first time in 1965 by Zadeh . T he present work represents the use of fuzzy logic to model and predict the experimental results of heat transfer in a double Pipe Heat Exchanger with Wavy (Corrugated) Twiste d Tape Inserts . The tape consists of the corrugations and the twisting with various twist ratios (TR=10.7,8.5,7.1) . The length,width and thickness of twisted tape were 1 m,14 mm and 2 mm respectively. The Reynolds number is varied from 5000 to 17 000. T he friction factor is varied from .0384 to .07241 . The Nusselt number is varied from 69.13 to 266.18. Here the results with various twist ratios tapes were compared with results with plain tube. The experimental results showed that the maximum heat tran sfer was obtained with twisted tape with TR � 7.1 . The Nusselt number increased by 172 % and friction factor value increased by 32.11% as compared to the smooth tube values. For Fuzzy Logic system the twist ratio,temperature and Reynolds Numbers were used as input functions and friction factor and Nusselt number were used as output functions. It is found that a fuzzy inference system named Mamdani is a powerful instrument for predicting the experiments due to its low error.
CFD Analysis of Heat Transfer in Helical CoilIRJET Journal
This document presents a computational fluid dynamics (CFD) analysis of heat transfer in a helical coil. The study aims to analyze the effect of coil diameter and inlet steam temperature on the heat transfer coefficient. CFD simulations are conducted for helical coils of different diameters with varying inlet steam temperatures and water flow rates. Results show that the heat transfer coefficient increases with increasing inlet steam temperature. Prior research on heat transfer in helical coils is also reviewed, focusing on studies utilizing CFD to analyze parameters like coil diameter, pitch, curvature ratio, and Reynolds number. The CFD methodology and boundary conditions used in this study are described. Contour plots of the simulated surface heat transfer coefficient are presented and discussed.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The results show that, with proper selection of physical parameters, significant heat transfer
enhancements and pressure drop reductions can be achieved simultaneously with porous pin fins and
the overall heat transfer performances in porous pin fin channels are much better than those in
traditional solid pin fin channels. The effects of pore density are significant. As PPI increases, the
pressure drops and heat fluxes in porous pin fin channels increase while the overall heat transfer
efficiencies decrease and the maximal overall heat transfer efficiencies are obtained at PPI 20.
Furthermore, the effects of pin fin form are also remarkable. With the same physical parameters, the
overall heat transfer efficiencies in the long elliptic porous pin fin channels are the highest while they
are the lowest in the short elliptic porous pin fin channels
This document summarizes a numerical study on heat transfer enhancement using porous pin fins in rectangular channels. The study uses ANSYS Fluent to simulate forced convection heat transfer under varying parameters like Reynolds number, pore density, and pin fin shape. Results show that porous pin fins can significantly enhance heat transfer and reduce pressure drop compared to solid pin fins. Higher pore density increases heat flux and pressure drop but lowers overall heat transfer efficiency. Long elliptic pin fins produce the highest efficiencies while short elliptic pins produce the lowest. Gaps in previous studies are identified, such as a lack of investigation into other working fluids like nanofluids and discrete heating of partially porous channels.
NUMERICAL ANALYSIS TO OPTIMIZE THE HEAT TRANSFER RATE OF TUBE-IN-TUBE HELICAL...Netha Jashuva
The document discusses numerical analysis to optimize the heat transfer rate of tube-in-tube helical coil heat exchangers. It begins with an introduction to heat exchangers and computational fluid dynamics (CFD) modeling. It then reviews previous literature on optimizing heat transfer rates in helical coil heat exchangers through varying parameters like coil diameter, pitch, fluid flow rates, and using nanofluids. The literature survey found that increasing the Dean number through these parameters generally increases heat transfer rates, though it also increases pumping power requirements. The goal of the project is to find the optimal point where increased heat transfer rates outweigh increased power needs.
NUMERICAL INVESTIGATION OF LAMINAR NANOFLUID FLOW IN MICRO CHANNEL HEAT SINKS IAEME Publication
The effect of using nanofluids on heat transfer and aerodynamics characteristics in rectangular shaped micro channel heat sink (MCHS) is numerically investigated for Reynolds number range of (100-400 ) and different value of heat flux (50 , 100, 150 ) / . In this study,the MCHS performance using tow type of nanofluid with volume
fraction 10% was used as a coolant is examined. The three-dimensional steady, laminar flow and heat transfer governing equations are solved using The computational fluid dynamics code (FLUENT). The MCHS performance is evaluated in terms of temperature profile, heat transfer,velocity profile, pressure drop and friction factor.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
Similar to Parametric investigations on the flow characteristics of a closed loop pulsating heat pipe a numerical study (20)
Submission Deadline: 30th September 2022
Acceptance Notification: Within Three Days’ time period
Online Publication: Within 24 Hrs. time Period
Expected Date of Dispatch of Printed Journal: 5th October 2022
MODELING AND ANALYSIS OF SURFACE ROUGHNESS AND WHITE LATER THICKNESS IN WIRE-...IAEME Publication
White layer thickness (WLT) formed and surface roughness in wire electric discharge turning (WEDT) of tungsten carbide composite has been made to model through response surface methodology (RSM). A Taguchi’s standard Design of experiments involving five input variables with three levels has been employed to establish a mathematical model between input parameters and responses. Percentage of cobalt content, spindle speed, Pulse on-time, wire feed and pulse off-time were changed during the experimental tests based on the Taguchi’s orthogonal array L27 (3^13). Analysis of variance (ANOVA) revealed that the mathematical models obtained can adequately describe performance within the parameters of the factors considered. There was a good agreement between the experimental and predicted values in this study.
A STUDY ON THE REASONS FOR TRANSGENDER TO BECOME ENTREPRENEURSIAEME Publication
The study explores the reasons for a transgender to become entrepreneurs. In this study transgender entrepreneur was taken as independent variable and reasons to become as dependent variable. Data were collected through a structured questionnaire containing a five point Likert Scale. The study examined the data of 30 transgender entrepreneurs in Salem Municipal Corporation of Tamil Nadu State, India. Simple Random sampling technique was used. Garrett Ranking Technique (Percentile Position, Mean Scores) was used as the analysis for the present study to identify the top 13 stimulus factors for establishment of trans entrepreneurial venture. Economic advancement of a nation is governed upon the upshot of a resolute entrepreneurial doings. The conception of entrepreneurship has stretched and materialized to the socially deflated uncharted sections of transgender community. Presently transgenders have smashed their stereotypes and are making recent headlines of achievements in various fields of our Indian society. The trans-community is gradually being observed in a new light and has been trying to achieve prospective growth in entrepreneurship. The findings of the research revealed that the optimistic changes are taking place to change affirmative societal outlook of the transgender for entrepreneurial ventureship. It also laid emphasis on other transgenders to renovate their traditional living. The paper also highlights that legislators, supervisory body should endorse an impartial canons and reforms in Tamil Nadu Transgender Welfare Board Association.
BROAD UNEXPOSED SKILLS OF TRANSGENDER ENTREPRENEURSIAEME Publication
Since ages gender difference is always a debatable theme whether caused by nature, evolution or environment. The birth of a transgender is dreadful not only for the child but also for their parents. The pain of living in the wrong physique and treated as second class victimized citizen is outrageous and fully harboured with vicious baseless negative scruples. For so long, social exclusion had perpetuated inequality and deprivation experiencing ingrained malign stigma and besieged victims of crime or violence across their life spans. They are pushed into the murky way of life with a source of eternal disgust, bereft sexual potency and perennial fear. Although they are highly visible but very little is known about them. The common public needs to comprehend the ravaged arrogance on these insensitive souls and assist in integrating them into the mainstream by offering equal opportunity, treat with humanity and respect their dignity. Entrepreneurship in the current age is endorsing the gender fairness movement. Unstable careers and economic inadequacy had inclined one of the gender variant people called Transgender to become entrepreneurs. These tiny budding entrepreneurs resulted in economic transition by means of employment, free from the clutches of stereotype jobs, raised standard of living and handful of financial empowerment. Besides all these inhibitions, they were able to witness a platform for skill set development that ignited them to enter into entrepreneurial domain. This paper epitomizes skill sets involved in trans-entrepreneurs of Thoothukudi Municipal Corporation of Tamil Nadu State and is a groundbreaking determination to sightsee various skills incorporated and the impact on entrepreneurship.
DETERMINANTS AFFECTING THE USER'S INTENTION TO USE MOBILE BANKING APPLICATIONSIAEME Publication
The banking and financial services industries are experiencing increased technology penetration. Among them, the banking industry has made technological advancements to better serve the general populace. The economy focused on transforming the banking sector's system into a cashless, paperless, and faceless one. The researcher wants to evaluate the user's intention for utilising a mobile banking application. The study also examines the variables affecting the user's behaviour intention when selecting specific applications for financial transactions. The researcher employed a well-structured questionnaire and a descriptive study methodology to gather the respondents' primary data utilising the snowball sampling technique. The study includes variables like performance expectations, effort expectations, social impact, enabling circumstances, and perceived risk. Each of the aforementioned variables has a major impact on how users utilise mobile banking applications. The outcome will assist the service provider in comprehending the user's history with mobile banking applications.
ANALYSE THE USER PREDILECTION ON GPAY AND PHONEPE FOR DIGITAL TRANSACTIONSIAEME Publication
Technology upgradation in banking sector took the economy to view that payment mode towards online transactions using mobile applications. This system enabled connectivity between banks, Merchant and user in a convenient mode. there are various applications used for online transactions such as Google pay, Paytm, freecharge, mobikiwi, oxygen, phonepe and so on and it also includes mobile banking applications. The study aimed at evaluating the predilection of the user in adopting digital transaction. The study is descriptive in nature. The researcher used random sample techniques to collect the data. The findings reveal that mobile applications differ with the quality of service rendered by Gpay and Phonepe. The researcher suggest the Phonepe application should focus on implementing the application should be user friendly interface and Gpay on motivating the users to feel the importance of request for money and modes of payments in the application.
VOICE BASED ATM FOR VISUALLY IMPAIRED USING ARDUINOIAEME Publication
The prototype of a voice-based ATM for visually impaired using Arduino is to help people who are blind. This uses RFID cards which contain users fingerprint encrypted on it and interacts with the users through voice commands. ATM operates when sensor detects the presence of one person in the cabin. After scanning the RFID card, it will ask to select the mode like –normal or blind. User can select the respective mode through voice input, if blind mode is selected the balance check or cash withdraw can be done through voice input. Normal mode procedure is same as the existing ATM.
IMPACT OF EMOTIONAL INTELLIGENCE ON HUMAN RESOURCE MANAGEMENT PRACTICES AMONG...IAEME Publication
There is increasing acceptability of emotional intelligence as a major factor in personality assessment and effective human resource management. Emotional intelligence as the ability to build capacity, empathize, co-operate, motivate and develop others cannot be divorced from both effective performance and human resource management systems. The human person is crucial in defining organizational leadership and fortunes in terms of challenges and opportunities and walking across both multinational and bilateral relationships. The growing complexity of the business world requires a great deal of self-confidence, integrity, communication, conflict and diversity management to keep the global enterprise within the paths of productivity and sustainability. Using the exploratory research design and 255 participants the result of this original study indicates strong positive correlation between emotional intelligence and effective human resource management. The paper offers suggestions on further studies between emotional intelligence and human capital development and recommends for conflict management as an integral part of effective human resource management.
VISUALISING AGING PARENTS & THEIR CLOSE CARERS LIFE JOURNEY IN AGING ECONOMYIAEME Publication
Our life journey, in general, is closely defined by the way we understand the meaning of why we coexist and deal with its challenges. As we develop the "inspiration economy", we could say that nearly all of the challenges we have faced are opportunities that help us to discover the rest of our journey. In this note paper, we explore how being faced with the opportunity of being a close carer for an aging parent with dementia brought intangible discoveries that changed our insight of the meaning of the rest of our life journey.
A STUDY ON THE IMPACT OF ORGANIZATIONAL CULTURE ON THE EFFECTIVENESS OF PERFO...IAEME Publication
The main objective of this study is to analyze the impact of aspects of Organizational Culture on the Effectiveness of the Performance Management System (PMS) in the Health Care Organization at Thanjavur. Organizational Culture and PMS play a crucial role in present-day organizations in achieving their objectives. PMS needs employees’ cooperation to achieve its intended objectives. Employees' cooperation depends upon the organization’s culture. The present study uses exploratory research to examine the relationship between the Organization's culture and the Effectiveness of the Performance Management System. The study uses a Structured Questionnaire to collect the primary data. For this study, Thirty-six non-clinical employees were selected from twelve randomly selected Health Care organizations at Thanjavur. Thirty-two fully completed questionnaires were received.
Living in 21st century in itself reminds all of us the necessity of police and its administration. As more and more we are entering into the modern society and culture, the more we require the services of the so called ‘Khaki Worthy’ men i.e., the police personnel. Whether we talk of Indian police or the other nation’s police, they all have the same recognition as they have in India. But as already mentioned, their services and requirements are different after the like 26th November, 2008 incidents, where they without saving their own lives has sacrificed themselves without any hitch and without caring about their respective family members and wards. In other words, they are like our heroes and mentors who can guide us from the darkness of fear, militancy, corruption and other dark sides of life and so on. Now the question arises, if Gandhi would have been alive today, what would have been his reaction/opinion to the police and its functioning? Would he have some thing different in his mind now what he had been in his mind before the partition or would he be going to start some Satyagraha in the form of some improvement in the functioning of the police administration? Really these questions or rather night mares can come to any one’s mind, when there is too much confusion is prevailing in our minds, when there is too much corruption in the society and when the polices working is also in the questioning because of one or the other case throughout the India. It is matter of great concern that we have to thing over our administration and our practical approach because the police personals are also like us, they are part and parcel of our society and among one of us, so why we all are pin pointing towards them.
A STUDY ON TALENT MANAGEMENT AND ITS IMPACT ON EMPLOYEE RETENTION IN SELECTED...IAEME Publication
The goal of this study was to see how talent management affected employee retention in the selected IT organizations in Chennai. The fundamental issue was the difficulty to attract, hire, and retain talented personnel who perform well and the gap between supply and demand of talent acquisition and retaining them within the firms. The study's main goals were to determine the impact of talent management on employee retention in IT companies in Chennai, investigate talent management strategies that IT companies could use to improve talent acquisition, performance management, career planning and formulate retention strategies that the IT firms could use. The respondents were given a structured close-ended questionnaire with the 5 Point Likert Scale as part of the study's quantitative research design. The target population consisted of 289 IT professionals. The questionnaires were distributed and collected by the researcher directly. The Statistical Package for Social Sciences (SPSS) was used to collect and analyse the questionnaire responses. Hypotheses that were formulated for the various areas of the study were tested using a variety of statistical tests. The key findings of the study suggested that talent management had an impact on employee retention. The studies also found that there is a clear link between the implementation of talent management and retention measures. Management should provide enough training and development for employees, clarify job responsibilities, provide adequate remuneration packages, and recognise employees for exceptional performance.
ATTRITION IN THE IT INDUSTRY DURING COVID-19 PANDEMIC: LINKING EMOTIONAL INTE...IAEME Publication
Globally, Millions of dollars were spent by the organizations for employing skilled Information Technology (IT) professionals. It is costly to replace unskilled employees with IT professionals possessing technical skills and competencies that aid in interconnecting the business processes. The organization’s employment tactics were forced to alter by globalization along with technological innovations as they consistently diminish to remain lean, outsource to concentrate on core competencies along with restructuring/reallocate personnel to gather efficiency. As other jobs, organizations or professions have become reasonably more appropriate in a shifting employment landscape, the above alterations trigger both involuntary as well as voluntary turnover. The employee view on jobs is also afflicted by the COVID-19 pandemic along with the employee-driven labour market. So, having effective strategies is necessary to tackle the withdrawal rate of employees. By associating Emotional Intelligence (EI) along with Talent Management (TM) in the IT industry, the rise in attrition rate was analyzed in this study. Only 303 respondents were collected out of 350 participants to whom questionnaires were distributed. From the employees of IT organizations located in Bangalore (India), the data were congregated. A simple random sampling methodology was employed to congregate data as of the respondents. Generating the hypothesis along with testing is eventuated. The effect of EI and TM along with regression analysis between TM and EI was analyzed. The outcomes indicated that employee and Organizational Performance (OP) were elevated by effective EI along with TM.
INFLUENCE OF TALENT MANAGEMENT PRACTICES ON ORGANIZATIONAL PERFORMANCE A STUD...IAEME Publication
By implementing talent management strategy, organizations would have the option to retain their skilled professionals while additionally working on their overall performance. It is the course of appropriately utilizing the ideal individuals, setting them up for future top positions, exploring and dealing with their performance, and holding them back from leaving the organization. It is employee performance that determines the success of every organization. The firm quickly obtains an upper hand over its rivals in the event that its employees having particular skills that cannot be duplicated by the competitors. Thus, firms are centred on creating successful talent management practices and processes to deal with the unique human resources. Firms are additionally endeavouring to keep their top/key staff since on the off chance that they leave; the whole store of information leaves the firm's hands. The study's objective was to determine the impact of talent management on organizational performance among the selected IT organizations in Chennai. The study recommends that talent management limitedly affects performance. On the off chance that this talent is appropriately management and implemented properly, organizations might benefit as much as possible from their maintained assets to support development and productivity, both monetarily and non-monetarily.
A STUDY OF VARIOUS TYPES OF LOANS OF SELECTED PUBLIC AND PRIVATE SECTOR BANKS...IAEME Publication
Banking regulations act of India, 1949 defines banking as “acceptance of deposits for the purpose of lending or investment from the public, repayment on demand or otherwise and withdrawable through cheques, drafts order or otherwise”, the major participants of the Indian financial system are commercial banks, the financial institution encompassing term lending institutions. Investments institutions, specialized financial institution and the state level development banks, non banking financial companies (NBFC) and other market intermediaries such has the stock brokers and money lenders are among the oldest of the certain variants of NBFC and the oldest market participants. The asset quality of banks is one of the most important indicators of their financial health. The Indian banking sector has been facing severe problems of increasing Non- Performing Assets (NPAs). The NPAs growth directly and indirectly affects the quality of assets and profitability of banks. It also shows the efficiency of banks credit risk management and the recovery effectiveness. NPA do not generate any income, whereas, the bank is required to make provisions for such as assets that why is a double edge weapon. This paper outlines the concept of quality of bank loans of different types like Housing, Agriculture and MSME loans in state Haryana of selected public and private sector banks. This study is highlighting problems associated with the role of commercial bank in financing Small and Medium Scale Enterprises (SME). The overall objective of the research was to assess the effect of the financing provisions existing for the setting up and operations of MSMEs in the country and to generate recommendations for more robust financing mechanisms for successful operation of the MSMEs, in turn understanding the impact of MSME loans on financial institutions due to NPA. There are many research conducted on the topic of Non- Performing Assets (NPA) Management, concerning particular bank, comparative study of public and private banks etc. In this paper the researcher is considering the aggregate data of selected public sector and private sector banks and attempts to compare the NPA of Housing, Agriculture and MSME loans in state Haryana of public and private sector banks. The tools used in the study are average and Anova test and variance. The findings reveal that NPA is common problem for both public and private sector banks and is associated with all types of loans either that is housing loans, agriculture loans and loans to SMES. NPAs of both public and private sector banks show the increasing trend. In 2010-11 GNPA of public and private sector were at same level it was 2% but after 2010-11 it increased in many fold and at present there is GNPA in some more than 15%. It shows the dark area of Indian banking sector.
EXPERIMENTAL STUDY OF MECHANICAL AND TRIBOLOGICAL RELATION OF NYLON/BaSO4 POL...IAEME Publication
An experiment conducted in this study found that BaSO4 changed Nylon 6's mechanical properties. By changing the weight ratios, BaSO4 was used to make Nylon 6. This Researcher looked into how hard Nylon-6/BaSO4 composites are and how well they wear. Experiments were done based on Taguchi design L9. Nylon-6/BaSO4 composites can be tested for their hardness number using a Rockwell hardness testing apparatus. On Nylon/BaSO4, the wear behavior was measured by a wear monitor, pinon-disc friction by varying reinforcement, sliding speed, and sliding distance, and the microstructure of the crack surfaces was observed by SEM. This study provides significant contributions to ultimate strength by increasing BaSO4 content up to 16% in the composites, and sliding speed contributes 72.45% to the wear rate
ROLE OF SOCIAL ENTREPRENEURSHIP IN RURAL DEVELOPMENT OF INDIA - PROBLEMS AND ...IAEME Publication
The majority of the population in India lives in villages. The village is the back bone of the country. Village or rural industries play an important role in the national economy, particularly in the rural development. Developing the rural economy is one of the key indicators towards a country’s success. Whether it be the need to look after the welfare of the farmers or invest in rural infrastructure, Governments have to ensure that rural development isn’t compromised. The economic development of our country largely depends on the progress of rural areas and the standard of living of rural masses. Village or rural industries play an important role in the national economy, particularly in the rural development. Rural entrepreneurship is based on stimulating local entrepreneurial talent and the subsequent growth of indigenous enterprises. It recognizes opportunity in the rural areas and accelerates a unique blend of resources either inside or outside of agriculture. Rural entrepreneurship brings an economic value to the rural sector by creating new methods of production, new markets, new products and generate employment opportunities thereby ensuring continuous rural development. Social Entrepreneurship has the direct and primary objective of serving the society along with the earning profits. So, social entrepreneurship is different from the economic entrepreneurship as its basic objective is not to earn profits but for providing innovative solutions to meet the society needs which are not taken care by majority of the entrepreneurs as they are in the business for profit making as a sole objective. So, the Social Entrepreneurs have the huge growth potential particularly in the developing countries like India where we have huge societal disparities in terms of the financial positions of the population. Still 22 percent of the Indian population is below the poverty line and also there is disparity among the rural & urban population in terms of families living under BPL. 25.7 percent of the rural population & 13.7 percent of the urban population is under BPL which clearly shows the disparity of the poor people in the rural and urban areas. The need to develop social entrepreneurship in agriculture is dictated by a large number of social problems. Such problems include low living standards, unemployment, and social tension. The reasons that led to the emergence of the practice of social entrepreneurship are the above factors. The research problem lays upon disclosing the importance of role of social entrepreneurship in rural development of India. The paper the tendencies of social entrepreneurship in India, to present successful examples of such business for providing recommendations how to improve situation in rural areas in terms of social entrepreneurship development. Indian government has made some steps towards development of social enterprises, social entrepreneurship, and social in- novation, but a lot remains to be improved.
OPTIMAL RECONFIGURATION OF POWER DISTRIBUTION RADIAL NETWORK USING HYBRID MET...IAEME Publication
Distribution system is a critical link between the electric power distributor and the consumers. Most of the distribution networks commonly used by the electric utility is the radial distribution network. However in this type of network, it has technical issues such as enormous power losses which affect the quality of the supply. Nowadays, the introduction of Distributed Generation (DG) units in the system help improve and support the voltage profile of the network as well as the performance of the system components through power loss mitigation. In this study network reconfiguration was done using two meta-heuristic algorithms Particle Swarm Optimization and Gravitational Search Algorithm (PSO-GSA) to enhance power quality and voltage profile in the system when simultaneously applied with the DG units. Backward/Forward Sweep Method was used in the load flow analysis and simulated using the MATLAB program. Five cases were considered in the Reconfiguration based on the contribution of DG units. The proposed method was tested using IEEE 33 bus system. Based on the results, there was a voltage profile improvement in the system from 0.9038 p.u. to 0.9594 p.u.. The integration of DG in the network also reduced power losses from 210.98 kW to 69.3963 kW. Simulated results are drawn to show the performance of each case.
APPLICATION OF FRUGAL APPROACH FOR PRODUCTIVITY IMPROVEMENT - A CASE STUDY OF...IAEME Publication
Manufacturing industries have witnessed an outburst in productivity. For productivity improvement manufacturing industries are taking various initiatives by using lean tools and techniques. However, in different manufacturing industries, frugal approach is applied in product design and services as a tool for improvement. Frugal approach contributed to prove less is more and seems indirectly contributing to improve productivity. Hence, there is need to understand status of frugal approach application in manufacturing industries. All manufacturing industries are trying hard and putting continuous efforts for competitive existence. For productivity improvements, manufacturing industries are coming up with different effective and efficient solutions in manufacturing processes and operations. To overcome current challenges, manufacturing industries have started using frugal approach in product design and services. For this study, methodology adopted with both primary and secondary sources of data. For primary source interview and observation technique is used and for secondary source review has done based on available literatures in website, printed magazines, manual etc. An attempt has made for understanding application of frugal approach with the study of manufacturing industry project. Manufacturing industry selected for this project study is Mahindra and Mahindra Ltd. This paper will help researcher to find the connections between the two concepts productivity improvement and frugal approach. This paper will help to understand significance of frugal approach for productivity improvement in manufacturing industry. This will also help to understand current scenario of frugal approach in manufacturing industry. In manufacturing industries various process are involved to deliver the final product. In the process of converting input in to output through manufacturing process productivity plays very critical role. Hence this study will help to evolve status of frugal approach in productivity improvement programme. The notion of frugal can be viewed as an approach towards productivity improvement in manufacturing industries.
A MULTIPLE – CHANNEL QUEUING MODELS ON FUZZY ENVIRONMENTIAEME Publication
In this paper, we investigated a queuing model of fuzzy environment-based a multiple channel queuing model (M/M/C) ( /FCFS) and study its performance under realistic conditions. It applies a nonagonal fuzzy number to analyse the relevant performance of a multiple channel queuing model (M/M/C) ( /FCFS). Based on the sub interval average ranking method for nonagonal fuzzy number, we convert fuzzy number to crisp one. Numerical results reveal that the efficiency of this method. Intuitively, the fuzzy environment adapts well to a multiple channel queuing models (M/M/C) ( /FCFS) are very well.
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und überflüssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
Discover top-tier mobile app development services, offering innovative solutions for iOS and Android. Enhance your business with custom, user-friendly mobile applications.
Skybuffer SAM4U tool for SAP license adoptionTatiana Kojar
Manage and optimize your license adoption and consumption with SAM4U, an SAP free customer software asset management tool.
SAM4U, an SAP complimentary software asset management tool for customers, delivers a detailed and well-structured overview of license inventory and usage with a user-friendly interface. We offer a hosted, cost-effective, and performance-optimized SAM4U setup in the Skybuffer Cloud environment. You retain ownership of the system and data, while we manage the ABAP 7.58 infrastructure, ensuring fixed Total Cost of Ownership (TCO) and exceptional services through the SAP Fiori interface.
Programming Foundation Models with DSPy - Meetup SlidesZilliz
Prompting language models is hard, while programming language models is easy. In this talk, I will discuss the state-of-the-art framework DSPy for programming foundation models with its powerful optimizers and runtime constraint system.
Ivanti’s Patch Tuesday breakdown goes beyond patching your applications and brings you the intelligence and guidance needed to prioritize where to focus your attention first. Catch early analysis on our Ivanti blog, then join industry expert Chris Goettl for the Patch Tuesday Webinar Event. There we’ll do a deep dive into each of the bulletins and give guidance on the risks associated with the newly-identified vulnerabilities.
HCL Notes and Domino License Cost Reduction in the World of DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-and-domino-license-cost-reduction-in-the-world-of-dlau/
The introduction of DLAU and the CCB & CCX licensing model caused quite a stir in the HCL community. As a Notes and Domino customer, you may have faced challenges with unexpected user counts and license costs. You probably have questions on how this new licensing approach works and how to benefit from it. Most importantly, you likely have budget constraints and want to save money where possible. Don’t worry, we can help with all of this!
We’ll show you how to fix common misconfigurations that cause higher-than-expected user counts, and how to identify accounts which you can deactivate to save money. There are also frequent patterns that can cause unnecessary cost, like using a person document instead of a mail-in for shared mailboxes. We’ll provide examples and solutions for those as well. And naturally we’ll explain the new licensing model.
Join HCL Ambassador Marc Thomas in this webinar with a special guest appearance from Franz Walder. It will give you the tools and know-how to stay on top of what is going on with Domino licensing. You will be able lower your cost through an optimized configuration and keep it low going forward.
These topics will be covered
- Reducing license cost by finding and fixing misconfigurations and superfluous accounts
- How do CCB and CCX licenses really work?
- Understanding the DLAU tool and how to best utilize it
- Tips for common problem areas, like team mailboxes, functional/test users, etc
- Practical examples and best practices to implement right away
AppSec PNW: Android and iOS Application Security with MobSFAjin Abraham
Mobile Security Framework - MobSF is a free and open source automated mobile application security testing environment designed to help security engineers, researchers, developers, and penetration testers to identify security vulnerabilities, malicious behaviours and privacy concerns in mobile applications using static and dynamic analysis. It supports all the popular mobile application binaries and source code formats built for Android and iOS devices. In addition to automated security assessment, it also offers an interactive testing environment to build and execute scenario based test/fuzz cases against the application.
This talk covers:
Using MobSF for static analysis of mobile applications.
Interactive dynamic security assessment of Android and iOS applications.
Solving Mobile app CTF challenges.
Reverse engineering and runtime analysis of Mobile malware.
How to shift left and integrate MobSF/mobsfscan SAST and DAST in your build pipeline.
What is an RPA CoE? Session 1 – CoE VisionDianaGray10
In the first session, we will review the organization's vision and how this has an impact on the COE Structure.
Topics covered:
• The role of a steering committee
• How do the organization’s priorities determine CoE Structure?
Speaker:
Chris Bolin, Senior Intelligent Automation Architect Anika Systems
Main news related to the CCS TSI 2023 (2023/1695)Jakub Marek
An English 🇬🇧 translation of a presentation to the speech I gave about the main changes brought by CCS TSI 2023 at the biggest Czech conference on Communications and signalling systems on Railways, which was held in Clarion Hotel Olomouc from 7th to 9th November 2023 (konferenceszt.cz). Attended by around 500 participants and 200 on-line followers.
The original Czech 🇨🇿 version of the presentation can be found here: https://www.slideshare.net/slideshow/hlavni-novinky-souvisejici-s-ccs-tsi-2023-2023-1695/269688092 .
The videorecording (in Czech) from the presentation is available here: https://youtu.be/WzjJWm4IyPk?si=SImb06tuXGb30BEH .
Dandelion Hashtable: beyond billion requests per second on a commodity serverAntonios Katsarakis
This slide deck presents DLHT, a concurrent in-memory hashtable. Despite efforts to optimize hashtables, that go as far as sacrificing core functionality, state-of-the-art designs still incur multiple memory accesses per request and block request processing in three cases. First, most hashtables block while waiting for data to be retrieved from memory. Second, open-addressing designs, which represent the current state-of-the-art, either cannot free index slots on deletes or must block all requests to do so. Third, index resizes block every request until all objects are copied to the new index. Defying folklore wisdom, DLHT forgoes open-addressing and adopts a fully-featured and memory-aware closed-addressing design based on bounded cache-line-chaining. This design offers lock-free index operations and deletes that free slots instantly, (2) completes most requests with a single memory access, (3) utilizes software prefetching to hide memory latencies, and (4) employs a novel non-blocking and parallel resizing. In a commodity server and a memory-resident workload, DLHT surpasses 1.6B requests per second and provides 3.5x (12x) the throughput of the state-of-the-art closed-addressing (open-addressing) resizable hashtable on Gets (Deletes).
Digital Banking in the Cloud: How Citizens Bank Unlocked Their MainframePrecisely
Inconsistent user experience and siloed data, high costs, and changing customer expectations – Citizens Bank was experiencing these challenges while it was attempting to deliver a superior digital banking experience for its clients. Its core banking applications run on the mainframe and Citizens was using legacy utilities to get the critical mainframe data to feed customer-facing channels, like call centers, web, and mobile. Ultimately, this led to higher operating costs (MIPS), delayed response times, and longer time to market.
Ever-changing customer expectations demand more modern digital experiences, and the bank needed to find a solution that could provide real-time data to its customer channels with low latency and operating costs. Join this session to learn how Citizens is leveraging Precisely to replicate mainframe data to its customer channels and deliver on their “modern digital bank” experiences.
Your One-Stop Shop for Python Success: Top 10 US Python Development Providersakankshawande
Simplify your search for a reliable Python development partner! This list presents the top 10 trusted US providers offering comprehensive Python development services, ensuring your project's success from conception to completion.
"Choosing proper type of scaling", Olena SyrotaFwdays
Imagine an IoT processing system that is already quite mature and production-ready and for which client coverage is growing and scaling and performance aspects are life and death questions. The system has Redis, MongoDB, and stream processing based on ksqldb. In this talk, firstly, we will analyze scaling approaches and then select the proper ones for our system.
In the realm of cybersecurity, offensive security practices act as a critical shield. By simulating real-world attacks in a controlled environment, these techniques expose vulnerabilities before malicious actors can exploit them. This proactive approach allows manufacturers to identify and fix weaknesses, significantly enhancing system security.
This presentation delves into the development of a system designed to mimic Galileo's Open Service signal using software-defined radio (SDR) technology. We'll begin with a foundational overview of both Global Navigation Satellite Systems (GNSS) and the intricacies of digital signal processing.
The presentation culminates in a live demonstration. We'll showcase the manipulation of Galileo's Open Service pilot signal, simulating an attack on various software and hardware systems. This practical demonstration serves to highlight the potential consequences of unaddressed vulnerabilities, emphasizing the importance of offensive security practices in safeguarding critical infrastructure.
2. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
272
1.2 Operating parameters
• Fill ratio
• Heat input
• Working fluid
• Dry out condition
Out of all, the diameter place a vital role in deciding whether or not the capillary flow exists inside of PHP. If the
diameter of a PHP is less than its critical diameter, capillary flow exists otherwise, flow gets stratified. The critical
diameter [4] is the maximum inner diameter causing the capillary flow and is defined as
Dcrit
(1)
A Pulsating Heat Pipe system looks simple, However understanding of its physics related to various processes
such as Thermo-Hydro dynamics, Two phase flow capillary actions, Phase change etc. is relatively complex. Therefore
many challenging issues remain modelled unsatisfactorily. The understanding of physical phenomena occurring in a PHP
is explained better from the experimental results. Quite a few attempts have been presented in the literature to model a
PHP system with various degrees of approximation and success. Shafiietal. [5] presented a multi plug model for heat
transfer estimation both for CEPHP and the CLPHP. In their model the total number vapour plugs were decreased to total
number of heating sections during simulation. Zhang and Faghri[6] proposed a multi plug model for Vertical CEPHP and
studied the effect of number of turns on the fluid oscillation frequency. Jang-Soo kim et al[7] developed a theoretical
model based on a separated flow model with two liquid slugs and three vapour plugs and investigated the effect of
diameter surface tension and fill ratio on the performances of the PHP. Khandekar and Groll [8]proposed lumped
parametric model for a single closed loop PHP. Xin-She Yang et al[9] devised a mathematical model to make the
predictions regarding the start-up characteristics.
In almost all the numerical studies the Thermo-Hydro Dynamic system in PHP is considered analogous to
forced damped vibration system. In some cases an attempt of applying the mass, momentum and energy equations to a
control volume of PHP has been done to obtain the mathematical model. But the experimental results have not been able
to match with mathematical models developed. A comprehensive mathematical model which could be used in the design
of PHP has eluded researches till now.
In all the above works pressure difference in evaporator and condenser is considered as driving force while the
heat transfer in PHP is studied. Whereas a mathematical model based on the temperature difference between evaporator
and condenser was proposed by Ma et.al [10] in order to deal with the pulsating behaviour of the fluid in a PHP. The
authors relate the pressure difference between evaporator and condenser with the temperature difference using Clasius-
Clapeyron's equation. The model was solved using Laplace Transforms and the slug displacements were obtained at
different operating parameters. The flow characteristics were derived for the PHP in the saturation region.
2. MATHEMATICAL MODEL
In the present work, parametric investigation on the flow characteristics of a single closed loop PHP has been carried
out through a numerical study. The Internal flow patterns in a PHP are function of the applied heat flux. Since slug flow is the
primary flow pattern in PHPs, most of the ongoing research works on modelling have focused on slug flow. The present work
adopts the mathematical model proposed by Ma et.al to study the slug flow characteristics of PHP. The governing differential
equations have been derived from the physical model shown in figure.1
Fig. 1: Schematic Diagram of PHP Considered For Analysis
3. Proceedings of the 2nd International Conference on Current Trends in Engineering and Management ICCTEM -2014
17 – 19, July 2014, Mysore, Karnataka, India
D − D
T T
max min t
=
d w
dx
A
+
l l v v v g
dx
A
273
The characteristic length of PHP consists of the length of evaporator section Le, adiabatic section La and
condenser section Lc. Hence,
e a c L = L + L + L
(2)
As the fluid flows in a PHP, the fluid gets evaporated in the evaporator and condensed in the condenser. This
results in the volume expansion and contraction of the bubbles. This causes an oscillating motion which affects the
saturation temperature in the evaporator and condenser section. If the maximum and minimum temperature difference
between the evaporator and condenser section are Tmax and Tmin respectively, then the temperature difference between
the evaporator and condenser section will vary between Tmax and Tmin and is given by
max min DT − DT
2
.Considering
the oscillating nature of PHP and system oscillation frequency as , the thermal driving potential can be written as
[1 cos( )]
D − D
T T
max min t
T + w
2
D =
(3)
The pressure difference between evaporator and condenser can be related to the thermal driving potential using
Clausius- Clapeyron's equation as.
fg e
T
e
h
p T
r
D = D
(4)
Hence the driving force causing the pulsating motion in a PHP is expressed as
[1 cos( )]
2
Ah
fg e
T
F
e
r
+
(5)
This driving force overcomes the (i) viscous force which arises due to the interaction between liquid/vapour and
the pipe walls (ii) force due to vapour pressure which arise due to volume contraction and expansion of bubbles and (iii)
force due to inertia (iv) capillary force due to meandering tube diameter.
From Newton’s law, the governing equation for fluid flow in a PHP is
[ ( )]
L L
d x
4. 2 2
[1 cos( )]
D −D
2
2 cos cos
2
( ) 32
max min
t
T T
Ah
fg v
T
R
A
x N
A R T
L
dt
D
dt
L L A
e
A R
v
l l v v
w
r
μ μ r s q q
r r
+
=
− +
+ +
+ +
(6)
The inertia force, the viscous force and the force due to vapour pressure in the above equation are given by
d x
2
2
( )
dt
F L L A i l l v v = r + r
(7)
dt
+
L L
5. F = 32
l l v v
vi D
2
μ μ
(8)
x
A R T
v g
L
F
v
vp
r
=
(9)
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2s − cosqA + cosqR A
274
Fcap= N
[ ( )]
R
(10)
The governing equation (6) for fluid flow in a PHP is similar to the governing equation of forced damped
mechanical vibration with the following initial conditions:
dx
x = 0And = 0
dt
at t = 0
In the present study to solve both slug displacement and slug velocity Embedded Runge-Kutta formula as given
in the MAT LAB with the nomenclature ODE 45[11] is used.
3. RESULTS AND DISCUSSION
Ma et.al work was limited only to study the effect of parameters on the displacement. Thus the first step in the
present study is to verify the patterns of present results with Ma et.al work. The refrigerants R12, R22, R123 and R134a
are used as the working fluids throughout the study. The slug velocity has been obtained from the solution of the
governing differential equations.
3.1 Parametric Studies on Displacement
3.1.1. Effect of working fluid
Fig. 2 Effect of Working Fluid on Displacement
(L = 304.8 mm, T = 300C, D = 1.65 mm, = 50%, T = 5K)
The variation of displacement with respect to time for R22, R123 and R134a with diameter of 1.65 mm, fill ratio
of 50% and operating temperature of 300C is shown in Fig. 2. It is clear from the figure that the frequency of oscillation
and amplitude are more in case of R22 compared to R123 and R134a. The system takes more time to reach the steady
state in case of R22.
3.1.2 Effect of fill ratio
Fig. 3 Effect Of Fill Ratio On Displacement
(R123, L = 304.8 mm, T = 300C, D = 1.65 mm, T = 5K)
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17 – 19, July 2014, Mysore, Karnataka, India
The variation of fill ratio has significant effect on the performance of PHP. Fill ratio is basically defined as [12]
275
f = =
Volume of Liquid
TotalVolume
2
D Ll
2
D L
p
4
p
4
Ll
=
L
The heat pipe works as true pulsating device in the range of 20-80% fill ratio [13]. Figure 3 shows the
comparison of fluid displacements with respect to the time for fill ratios of 50%, 60% and 70% with R123 as the working
fluid at diameter of 1.65mm, operating temperature of 300C and T = 5K. It can be seen from Fig. 3 that the time to
reach the steady state increases with decrease in fill ratio. The amplitude of displacement is inversely proportional to the
fill ratio.
3.1.3 Effect of diameter
Fig. 4 Effect of Diameter on Displacement
(R123, L = 304.8 mm, T = 300C, D = 1.65 mm, = 50%, T = 5K)
The variation of displacement with respect to time for different diameters with R123 as the working fluid with
fill ratio of 50% at operating temperature of 300C and T = 5K is shown in Fig. 4. It is reported in the literature that the
maximum diameter that can hold a vapour bubble in a PHP tube is 2.5 mm [5]. In the present study, three diameters of
1.14 mm, 1.65 mm and 2.16 mm are considered. It can be observed from Fig. 4 that the amplitude of displacement is
directly proportional to the diameter. The frequency of oscillation remains same for all the diameters studied. With the
increase in diameter, The system takes more time to reach the steady state.
3.1.4 Effect of operating temperature
Fig. 5 Effect of Operating Temperature on Displacement
(R123, L = 304.8 mm, T = 300C, D = 1.65 mm, = 50%, T = 5K)
The operating temperature has a significant effect on the fluid flow characteristics of a PHP. A change in the
operating temperature results in considerable change in the energy levels of the fluid. Fig. 5 shows the variation of
displacement as a function of time at different operating temperatures for R123 with diameter of 1.65 mm and fill ratio of
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17 – 19, July 2014, Mysore, Karnataka, India
50%. With increase in the operating temperature an increase in the amplitude of displacements can be observed. It is also
seen that with increase in the operating temperature the frequency of oscillation also increases.
276
3.2 Parametric Studies on Slug Velocity
3.2.1 Effect of fill ratio
Fig. 6 Effect of Fill Ratio on Slug Velocity
(R123, L = 304.8 mm, T = 300C, D = 1.65 mm, = 50%, T = 5K)
Fig. 6 shows the variation of root mean square values of velocity of the slug with respect to time for different fill
ratio with R123 as the working fluid at diameter of 1.65 mm and operating temperature of 300C. Considering the
pulsating nature of fluid flow in a PHP, the root mean square values of velocity are evaluated for each cycle and plotted
with respect to time. The momentum of the fluid is less in the initial time steps resulting in lower slug velocity. The slug
velocity increases with increase in time and reaches saturation at elapsed time as the fluid gains momentum as shown in
Fig. 6.
The variation of fill ratio shows a significant effect on the performance of PHP. In the present study, the fill
ratio is varied in the range of 50% to 70%. It is observed from Fig. 6 that due to the prevalence of more fluid
displacement at lower fill ratios consequently higher slug velocities are observed at lower fill ratios.
3.2.2 Effect of diameter
Fig. 7: Effect of Diameter on Slug Velocity
(R123, L = 304.8mm, T = 300C, D = 1.65 mm, = 50%, T = 5K)
The variation of slug velocity with respect to time for different diameters with R123 as the working fluid with
fill ratio of 50% at operating temperature of 300C is shown in Fig. 7. Due to inertia, the velocity of the slug remains
almost same at all diameters in the initial time steps. But with the increase in the momentum of the fluid, the velocity of
the slug shows an increasing trend with an increase in diameter. Due to the reduction in viscous force the resistance to the
fluid flow decreases with increase in diameter as seen from equation (6). Hence, higher slug velocities are observed at
higher diameter. It is also seen that larger time has been taken place to attain the steady state by the system at higher
diameter.
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17 – 19, July 2014, Mysore, Karnataka, India
277
3.2.3 Effect of operating temperature
Fig. 8: Effect of Operating Temperature on Slug Velocity
(R123, L = 304.8 mm, T = 300C, D = 1.65 mm, = 50%, T = 5K)
Fig. 8 shows the variation of velocity of the slug as a function of time at different operating temperatures for
R123 with diameter of 1.65 mm and fill ratio of 50%. The thermal energy available for the momentum of the working
fluid is directly proportional to operating temperature. This results in higher slug velocity at higher operating
temperature. It is also seen that the momentum of the fluid is very less at 100C and 200C as the displacement of the fluid
is less due to lower thermal energy. Hence it is advisable to operate PHP at higher operating temperatures.
3.2.4 Effect of working fluid
Fig. 9: Effect of Working Fluid on Slug Velocity
(R123, L = 304.8 mm, T = 300C, D = 1.65 mm, = 50%, T = 5K)
The variation of RMS slug velocity with respect to time for different working fluids with diameter of 1.65 mm,
fill ratio of 50% and operating temperature of 300C is shown in Fig. 9. It is observed that the magnitude of slug velocities
is optimum for R32 compared to R22, R134a and R123. Higher values of slug velocities for R32 can be attributed to its
lower value of latent heat.
3.2.5 Effect of temperature difference
Fig. 10: Effect of Temperature Difference on Slug Velocity
(R123, L = 304.8 mm, T = 300C, D = 1.65 mm, = 50%)
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17 – 19, July 2014, Mysore, Karnataka, India
278
In the present study, the temperature difference between the evaporator and condenser is taken as the driving
force for the fluid motion. A variation in this value of temperature difference results in a change in the momentum
transport and heat transport values. Fig. 10 shows the effect of this temperature difference between evaporator and
condenser on the slug velocity for R123 at fill ratio of 50%, diameter of 1.65mm and operating temperature of 300C. It is
clear from Fig. 10 that the slug velocities is directly proportional to the temperature difference. As the energy level
increases at higher temperature difference, it results in better momentum and hence better heat transport. Thus it is
desirable to operate the PHP with higher temperature difference between the evaporator and condenser.
3.2.6 Influence of forces on pulsating flow
Fig. 11 Influence of forces on pulsating Flow
4. CONCLUSIONS
The following conclusions have been made from the numerical study
• The pulsating flow characteristics in a PHP are analysed by the present study.
• Higher slug velocities are associated with lower fill ratio, higher diameter, higher operating temperature and
higher temperature difference between evaporator and condenser.
• Higher values of slug velocities are observed in case of R123. This shows that R123 exhibits better fluid flow
characteristics of PHP compared to other refrigerants.
• The effect of capillary forces found to be significant at lower diameter, lower operating temperature, higher fill
ratio and lower temperature difference between evaporator and condenser.
• It has been observed that the inertia force is a predominant opposing force compared to other forces.
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17 – 19, July 2014, Mysore, Karnataka, India
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