This document describes a numerical simulation and optimization of cooling tubes in a distribution transformer to improve heat transfer efficiency. Five optimization cases are studied: 1) normal case without modifications, 2) implanting axial grooves and fins in cooling tubes, 3) adding a porous media inside tubes, 4) combining porous media with axial grooves and fins, and 5) inclining the cooling tubes. The simulation is performed using ANSYS Fluent to model fluid flow and heat transfer. The results are analyzed to determine the maximum hot spot temperatures and evaluate which case provides the most efficient cooling of the transformer core and windings.
Experimentation and analysis of heat transfer through perforated fins of diff...SharathKumar528
Engineering Project by Abhijath HB, Dashartha H S, Akshay Mohanraj and Sharath Kumar M S involving analysis of Fins( Heat exchanging extensions) with various geometrical perforations.
Boiling and Condensation heat transfer -- EES Functions and Procedurestmuliya
This file contains notes on Engineering Equation Solver (EES) Functions and Procedures for Boiling and Condensation heat transfer. Some problems are also included.
These notes were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India.
Contents: Summary of formulas used -
EES Functions/Procedures for boiling: Nucleate boiling heat flux for any geometry - critical heat flux for large horizontal surface, horizontal cylinder and sphere - Film boiling for horizontal cylinder, sphere and horizontal surface – Problems.
EES Functions/Procedures for condensation of: steam on vertical surface – any fluid on a vertical surface – steam on vertical cylinder – any fluid on vertical cylinder – steam on horizontal cylinder – any fluid on horizontal cylinder – steam on a horizontal tube bank – any fluid on horizontal tube bank – any fluid on a sphere – any fluid inside a horizontal cylinder - Problems.
It is hoped that these notes will be useful to teachers, students, researchers and professionals working in this field.
Research Inventy : International Journal of Engineering and Scienceinventy
Research Inventy : International Journal of Engineering and Science
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed
EXPERIMENTAL STUDY OF HEAT TRANSFER FROM PLATE FIN ARRAY IN MIXED CONVECTION ...ijiert bestjournal
The work summarized in this paper presents an exper imental study of heat transfer from plate fin in mixed convection mode enhancement by the us e of plate fins is presented. After a brief review of the basic methods used to enhance the hea t transfer by simultaneous increase of heat transfer surface area as well as the heat tran sfer coefficient,a simple experimental method to assess the heat transfer enhancement is p resented. The method is demonstrated on plate fins as elements for the heat transfer enhanc ement,but it can in principle be applied also to other fin forms. That is varying various paramet ers (height,spacing). The order of the magnitude of heat transfer enhancement obtained exp erimentally,it was found that by a direct comparison of Nu and Re no conclusion regarding the relative performances could be made. This is because the dimensionless variables are int roduced for the scaling of heat transfer and pressure drop results from laboratory to large scal e but not for the performance comparison. Therefore a literature survey of the performance co mparison methods used in the past was also performed. Experiments will carried out on mix ed convection heat transfer from plate fin heat sinks subject to the influence of its geometry and heat flux. A total of 9 plate fins were pasted into the upper surface of the base plate. Th e area of the base plate is 150mm by 150mm. The base plate and the fins were made of alu minum. For all tested plate fin heat sinks,however,the heat transfer performance for h eat sinks with plate fins was better than that of solid pins.
Experimentation and analysis of heat transfer through perforated fins of diff...SharathKumar528
Engineering Project by Abhijath HB, Dashartha H S, Akshay Mohanraj and Sharath Kumar M S involving analysis of Fins( Heat exchanging extensions) with various geometrical perforations.
Boiling and Condensation heat transfer -- EES Functions and Procedurestmuliya
This file contains notes on Engineering Equation Solver (EES) Functions and Procedures for Boiling and Condensation heat transfer. Some problems are also included.
These notes were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India.
Contents: Summary of formulas used -
EES Functions/Procedures for boiling: Nucleate boiling heat flux for any geometry - critical heat flux for large horizontal surface, horizontal cylinder and sphere - Film boiling for horizontal cylinder, sphere and horizontal surface – Problems.
EES Functions/Procedures for condensation of: steam on vertical surface – any fluid on a vertical surface – steam on vertical cylinder – any fluid on vertical cylinder – steam on horizontal cylinder – any fluid on horizontal cylinder – steam on a horizontal tube bank – any fluid on horizontal tube bank – any fluid on a sphere – any fluid inside a horizontal cylinder - Problems.
It is hoped that these notes will be useful to teachers, students, researchers and professionals working in this field.
Research Inventy : International Journal of Engineering and Scienceinventy
Research Inventy : International Journal of Engineering and Science
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed
EXPERIMENTAL STUDY OF HEAT TRANSFER FROM PLATE FIN ARRAY IN MIXED CONVECTION ...ijiert bestjournal
The work summarized in this paper presents an exper imental study of heat transfer from plate fin in mixed convection mode enhancement by the us e of plate fins is presented. After a brief review of the basic methods used to enhance the hea t transfer by simultaneous increase of heat transfer surface area as well as the heat tran sfer coefficient,a simple experimental method to assess the heat transfer enhancement is p resented. The method is demonstrated on plate fins as elements for the heat transfer enhanc ement,but it can in principle be applied also to other fin forms. That is varying various paramet ers (height,spacing). The order of the magnitude of heat transfer enhancement obtained exp erimentally,it was found that by a direct comparison of Nu and Re no conclusion regarding the relative performances could be made. This is because the dimensionless variables are int roduced for the scaling of heat transfer and pressure drop results from laboratory to large scal e but not for the performance comparison. Therefore a literature survey of the performance co mparison methods used in the past was also performed. Experiments will carried out on mix ed convection heat transfer from plate fin heat sinks subject to the influence of its geometry and heat flux. A total of 9 plate fins were pasted into the upper surface of the base plate. Th e area of the base plate is 150mm by 150mm. The base plate and the fins were made of alu minum. For all tested plate fin heat sinks,however,the heat transfer performance for h eat sinks with plate fins was better than that of solid pins.
Heat transfer from extended surfaces (or fins)tmuliya
This file contains slides on Heat Transfer from Extended Surfaces (FINS). The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India.
Contents: Governing differential eqn – different boundary conditions – temp. distribution and heat transfer rate for: infinitely long fin, fin with insulated end, fin losing heat from its end, and fin with specified temperatures at its ends – performance of fins - ‘fin efficiency’ and ‘fin effectiveness’ – fins of non-uniform cross-section- thermal resistance and total surface efficiency of fins – estimation of error in temperature measurement - Problems
STUDY OF HEAT TRANSFER ON BROKEN ARC ROUGHNESS ELEMENTS ON THE ABSORBER PLATE...IAEME Publication
Performance of solar air heater can be enhanced by adding roughness to the inner periphery. The present study on the effect of various shape parameters for broken arc roughness elements of heat transfer and friction factor characteristics of rectangular duct. The duct has Reynolds number (Re) range of 3000-22300, respective roughness height (e/D) values is 0.045, arc angle (α) is 60˚ and roughness width (W/w) is 5 and relatively roughness pitch is 8.
Experimental study on heat transfer and friction factor characteristics in la...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Comparative Study of ECONOMISER Using the CFD Analysis IJMER
This paper presents a simulation of the economizer zone, which allowsstudying the flow
patterns developed in the fluid, while it flows along the length of the economizer. The past failure
details revelsthat erosion is more in U-bend areas of Economizer Unit because of increase in flue gas
velocity near these bends. But it isobserved that the velocity of flue gases surprisingly increases near
the lower bends as compared to upper ones. The model issolved using conventional CFD techniques by
FLUENT software. In which the individual tubes are treated as sub-gridfeatures. A geometrical model
is used to describe the multiplicity of heat-exchanging structures and the interconnectionsamong them.
The Computational Fluid Dynamics (CFD) approach is utilised for the creation of a three-dimensional
modelof the economizer coil of single column tube. With equilibrium assumption applied for
description of the system chemistry. The flue gastemperature, pressure and velocity field of fluid flow
within an economizer tube using the actual bounda
Introduction to transient Heat conduction, Lamped System Analysis, Approxiamate Analytical and graphical method and Numerical method for one and two dimensional heat conduction by using Explicit and Implicit method
Make Animated Videos With Explaindio,
Explaindio Make Animated Videos,
Kill your Competition with Explaindio Animated Videos,
How to Dominate your Business with Explaindio Animated Videos,
Heat transfer from extended surfaces (or fins)tmuliya
This file contains slides on Heat Transfer from Extended Surfaces (FINS). The slides were prepared while teaching Heat Transfer course to the M.Tech. students in Mechanical Engineering Dept. of St. Joseph Engineering College, Vamanjoor, Mangalore, India.
Contents: Governing differential eqn – different boundary conditions – temp. distribution and heat transfer rate for: infinitely long fin, fin with insulated end, fin losing heat from its end, and fin with specified temperatures at its ends – performance of fins - ‘fin efficiency’ and ‘fin effectiveness’ – fins of non-uniform cross-section- thermal resistance and total surface efficiency of fins – estimation of error in temperature measurement - Problems
STUDY OF HEAT TRANSFER ON BROKEN ARC ROUGHNESS ELEMENTS ON THE ABSORBER PLATE...IAEME Publication
Performance of solar air heater can be enhanced by adding roughness to the inner periphery. The present study on the effect of various shape parameters for broken arc roughness elements of heat transfer and friction factor characteristics of rectangular duct. The duct has Reynolds number (Re) range of 3000-22300, respective roughness height (e/D) values is 0.045, arc angle (α) is 60˚ and roughness width (W/w) is 5 and relatively roughness pitch is 8.
Experimental study on heat transfer and friction factor characteristics in la...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Comparative Study of ECONOMISER Using the CFD Analysis IJMER
This paper presents a simulation of the economizer zone, which allowsstudying the flow
patterns developed in the fluid, while it flows along the length of the economizer. The past failure
details revelsthat erosion is more in U-bend areas of Economizer Unit because of increase in flue gas
velocity near these bends. But it isobserved that the velocity of flue gases surprisingly increases near
the lower bends as compared to upper ones. The model issolved using conventional CFD techniques by
FLUENT software. In which the individual tubes are treated as sub-gridfeatures. A geometrical model
is used to describe the multiplicity of heat-exchanging structures and the interconnectionsamong them.
The Computational Fluid Dynamics (CFD) approach is utilised for the creation of a three-dimensional
modelof the economizer coil of single column tube. With equilibrium assumption applied for
description of the system chemistry. The flue gastemperature, pressure and velocity field of fluid flow
within an economizer tube using the actual bounda
Introduction to transient Heat conduction, Lamped System Analysis, Approxiamate Analytical and graphical method and Numerical method for one and two dimensional heat conduction by using Explicit and Implicit method
Make Animated Videos With Explaindio,
Explaindio Make Animated Videos,
Kill your Competition with Explaindio Animated Videos,
How to Dominate your Business with Explaindio Animated Videos,
The heat transfer and friction factor were
experimentally investigated in a louvered strip inserted tube in
turbulent flow region. A copper tube of (I.D=28mm, O.D=32mm)
and 900mm length was used. A louvered strip insert with
different geometrical configuration was inserted into the smooth
tube. A uniform heat flux condition was created by wrapping
heating tape of 2500 watt around the test section. Fibre glass
cloth was used as a thermal insulator which surrounds the
heating tape. Outer surface temperature of the tube were
measured at five different equally spaced points of test section by
k-typethermocouples. Two thermocouples were used to measure
the inlet and outlet temperature of water. The Reynolds numbers
were varied in the range of 2500 to 4000 with constant heat flux
of 24 kw/m2 for smooth tube and louvered strip inserted. Nusselt
number and friction factor obtained for louvered strip (with
forward backward arrangement) > Nusselt number and friction
factor for louvered strip (with semi-forward semi-backward
arrangement)> Nusselt number and friction factor for louvered
strip (with forward arrengement).
AN EXPERIMENTAL STUDY OF EXERGY IN A CORRUGATED PLATE HEAT EXCHANGERIAEME Publication
In the present work an attempt has been made to investigate the performance of a 3 channel 1-1 pass, corrugated plate heat exchanger. The plates had sinusoidal wavy surfaces with corrugation angle of 450. Hot water at different inlet temperature ranging from 400C to 600C was made to flow in the central channel to get cooled by water in the outer channels.
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.
Analysis of Natural Convention Heat Transfer Enhancement in Finned Tube Heat ...journal ijrtem
ABSTRACT: Most of the engineering problems require high performance heat transfer components with progressively less weight, volumes, accommodating shapes and costs. Air cooled heat exchangers are subjected to air on outer side of heat exchanger surface on in heat recovery systems like economizers gases are subjected on one side of tube surface. On air or gas side heat transfer coefficient is less. Extended surface (fins) are one of the next exchanging devices that are employed extensively to increase heat transfer rates from tubular heat exchangers. The rate of heat transfer depends on the surface area of fin available for exchanging the heat transfer rate from the primary surface of cylindrical shape. Present study focuses on enhancement of heat transfer by using both circular and elliptical type of fins. The present paper attempts to examine trend of heat transfer coefficient experimentally and by using CFD software for various types of elliptical fins with i) varying elliptical ratio, ii) changing orientation of mounting of heat exchanger tube with elliptical fins, iii) varying spacing or fin density. KEY WORDS: Natural convection, Heat transfer enhancements, Elliptical fin, Fin orientation, Fin density.
HEAT TRANSFER AND FLOW FRICTION CHARACTERISTICS OF SOLAR WATER HEATER WITH IN...IAEME Publication
Experimental investigation of friction factor and heat transfer characteristics of thermosyphone solar water heater with flat plate solar collector fitted with full length baffle of 10cm
pitch have been presented. The flow regime is laminar for this study with the Reynolds number range 124 to 258. The experimental data obtained were compared with those obtained from plain tube data. The effects of full length baffle inside the tube on heat transfer and friction factor were presented.
DESIGN, ANALYSIS AND PERFORMANCE INVESTIGATION OF HEAT EXTRACTION UNIT USING ...Journal For Research
Over the last years, there has been growing interest in applying new technologies to improve the heat transfer from the various heat sources such as geothermal energy, power plants, diesel engines, automobiles and other industrial heat-generating process. The heat transfer enhancement by means of extended surface type heat exchanger is well established technology and at present being adopted by most of the waste heat recovery system. Different types of heat transfer enhancement techniques using fins are available in extended surface type heat exchanger but each of this technique having different heat transfer enhancement ratio. Different researchers have analyzed the effect of fin geometry and combination of fins on heat transfer enhancement technique. In present research, find out the effect of fins on heat transfer augmentation or heat transfer coefficient for extracting heat from various waste heat sources.
Cooling Of Power Converters by Natural ConvectionIJERA Editor
This paper discusses the numerical analysis of the effect of a discontinuous heat flux on heat transfer by natural convection along a vertical flat plate or in a rectangular channel. The objective of this study is to determine the effect of a discrete distribution of the heat flux on the cooling of twelve resistors, which represent electronic components, that are mounted on an aluminium vertical plate. The results of the simulations show that the distribution of the heat flux significantly influences the heat transfer.
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.
Optimization of a Shell and Tube Condenser using Numerical MethodIJERA Editor
The purpose of this study was to investigate the effect of installation of the tube external surfaces, their parameter and variable in a shell-and-tube condenser. Variation of heat transfer coefficient with each variable of shell and tube condenser was measured each test. The optimization tube outside diameter size was analyzed and use extended surface area attached tube with tube material and tube layout and arrangement (Number of tube a triangular or hexagonal arrangement) on shell-and tube condenser. The computer programming was used to get faster output in less time. Results suggest that mean heat transfer coefficient in variable condition were mainly at velocity is fixed. And also average additional surfaces and tube layout and the arrangement comparison with the quantity of the heat transfer.
NUMERICAL INVESTIGATION OF NATURAL CONVECTION HEAT TRANSFERFROM SQUARE CYLIND...ijmech
The enhancement of natural convection heat transfer using nanofluids from horizontal square cylinder
placed in a square enclosure is investigated numerically. Water-based Cu is used as the working nanofluid.
The investigation covered a range of Rayleigh numbers of 104
- 106
, nanoparticles volume fraction of
(0<ϕ≤0.2), enclosure width to cylinder height ratio, W/H of 2.5. The investigation includes the solution of
the governing equations in the Vorticity-Stream function space with the aid of a body fitted coordinate
system. Algebraic grid generation is used in the initial transformations, followed by an elliptic
transformation to complete the grid generation to computational domain. The resulting discretized system
of equations is solved using an ADI method. The built code is validated and the results showed an increase
in average Nusselt number with increasing the volume fraction of the nanoparticles for the whole range of
Rayleigh number. The isotherms are nearly similar when the volume fraction of nanoparticles is increased
from 0 to 0.2 for each Rayleigh number but a change in the streamlines is observed.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
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.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
Contact with Dawood Bhai Just call on +92322-6382012 and we'll help you. We'll solve all your problems within 12 to 24 hours and with 101% guarantee and with astrology systematic. If you want to take any personal or professional advice then also you can call us on +92322-6382012 , ONLINE LOVE PROBLEM & Other all types of Daily Life Problem's.Then CALL or WHATSAPP us on +92322-6382012 and Get all these problems solutions here by Amil Baba DAWOOD BANGALI
#vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore#blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #blackmagicforlove #blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #Amilbabainuk #amilbabainspain #amilbabaindubai #Amilbabainnorway #amilbabainkrachi #amilbabainlahore #amilbabaingujranwalan #amilbabainislamabad
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Simulation and Optimization of Cooling Tubes of Transformer for Efficient Heat Transfer
1. International Journal of Advanced Engineering, Management and Science (IJAEMS) [Vol-3, Issue-2, Feb- 2017]
https://dx.doi.org/10.24001/ijaems.3.2.23 ISSN : 2454-1311
www.ijaems.com Page | 141
Simulation and Optimization of Cooling Tubes of
Transformer for Efficient Heat Transfer
Jackwin Vincent K, Dr V.V.Prathibha Bharathi
1
Department of mechanical Engineering, Malla Reddy college of Engineering, Secunderabad, India
Abstract— Temperature variation with in the transformer
affects the life and efficiency of the distribution
transformer. The top oil temperature in the transformer
depends on the type of cooling and cooling ducts/fins
design and their layout. The present project investigates
methods of onan transformer cooling system by means of
increasing heat transfer rate by implanting the axial
groves along with fins and porous region within in the
cooling tubes and further optimization of the cooling
process by adjusting the gravity by orienting the tube.
This study is carried out by means of numerical analysis
by simulating Transformer geometry in Ansys Fluent
.Real case geometry of distribution transformer is used in
this simulation
Keywords— Ansys Fluent, CFD, Distribution
transformer cooling, numerical Analysis, Optimization
I. INTRODUCTION
There are several factors contributing to power losses in
transformers. These are copper losses, which represent the
major source of losses in a transformer, and core losses;
namely hysteresis and eddy current losses. These losses
components are produced in the form of heat energy
which should be dissipated in a quick and rather efficient
manner. If the transformer has otherwise failed to get rid
of such heat generated, many problems could arise and in
some cases severe consequences may occur.
In fact, the improperly dissipated heat would further
accumulate and thus cause the transformer temperature to
increase. This process may lead to failure of paper
insulation and liquid insulation medium of the
transformer. Furthermore, excessive heat may result in
damage of the transformer windings, the matter which, in
particular, is considered as a catastrophe for expensive
high power rating transformers. Therefore, numerous
ways are introduced to keep the temperature within
acceptable limits which in turn would help to maintain a
long lifetime of the transformer. One such way is onan
cooling of transformer which means oil natural air natural
which is in distribution transformer. This method makes
use of natural convection of transformer oil and air.
The present project investigates methods of transformer
cooling system by means of increasing heat transfer rate
by implanting the axial groves along with fins and porous
region within in the cooling tubes. And further
optimization of the cooling process by adjusting the
gravity by orienting the tube. Five optimization cases is
studied This study is carried out by means of numerical
analysis by simulating Transformer geometry in Ansys
Fluent.
An experimental investigation of Temperature
distribution in a distribution transformer and Experiment
investigation of free convection heat transfer from an
array of vertical tube is carried out by
A.Satyanarayana.Reddy, Suresh Akella, and AMK.
Prasad [1][2].Thermal modeling of natural convection
cooled oil immersed distribution transformer is carried
out by Robert Michael Marko[3]. Transformer cooling
system improvement has been extensively studied
through analytical or advanced numerical techniques by
Miguel E. Rosillo[5]. Eleftherios I. Amoiralis and Stefan
D.L. ŢĂLU [4] developed a method for optimum
transformer tank panels geometry for the cooling system.
Y. X. Wang, H. B. Ma and G. P. Peterson [6] did
Investigation of the Temperature Distribution on Radiator
Fins with Micro Heat Pipes.
S.A.Nada and M.Mowad [7] performed an experimental
study on free convection from a vertical and inclined
semicircular cylinder at different orientations at constant
heat flux. The experiments were carried at four inclination
angles (0˚, 30˚, 45˚ and 60˚) of the semicircular cylinder.
The results showed that the average Nusselt number
increases as the inclination angle of the semicircular
cylinder increases. Alegi, g. and Black simulated Real-
time thermal mode1 for an oil immersed forced-air cooled
transformer. They contributed the study of forced
convection in the area of distribution transformer.
II. IMPROVEMENT OF TRANSFORMER
COOLING SYSTEM
The transformer consists of a closed magnetic circuit (the
core) with two coils, or windings, of insulated conductors
wound around the core. The current in the input, or
primary, coil creates a magnetic field. This field induces a
voltage across the output, or secondary coil. The
secondary coil of a distribution transformer is designed to
deliver energy at a lower level of voltage relative to the
input voltage. For a distribution transformer, the high
2. International Journal of Advanced Engineering, Management and Science (IJAEMS) [Vol-3, Issue-2, Feb- 2017]
https://dx.doi.org/10.24001/ijaems.3.2.23 ISSN : 2454-1311
www.ijaems.com Page | 142
voltage winding is the primary coil and the low voltage
winding is the secondary coil.
As the current passes through the copper or Aluminum
windings, energy is lost because of electrical resistance
power losses (Power = current2 x Resistance). The energy
losses raise the temperature of the windings. Various
methods of dissipating energy to the surroundings are
employed to cool the windings. The temperature rise is
controlled by transferring energy generated from the
transformer to a cooling fluid, such as oil or air. Excess
heating accelerates the aging of the transformer
insulation.
When the oil paper insulation is subjected to thermal
stress, the oil and paper components of the insulation may
be irreversibly damaged. The thermal stress reduces the
mechanical and dielectric performance of the insulation
.There is a need to optimize the design and application of
transformers. Manufacturers and utilities try to reduce the
capital and operational costs of transformers. The main
objectives of this Project are:
Numerical simulation of natural convection
process in a onan distribution transformer and find
out maximum hot spot temperature at the core and
windings
To carry out design optimization in cooling tubes
to increase heat transfer and to reduce hot spot
temperature of core.
Comparative study of five optimization cases for
efficient heat transfer
Case 1: normal case without any modification
Case 2: Implanting axial grooves with fins in
cooling tubes
Case 3: With porous media inside cooling tubes
Case 4: With porous media and axial grooves with
fins inside tubes.
Case 5: With inclination of cooling tubes
III. NUMERICAL SIMULATION AND
OPTIMIZATION
The fluid flow and heat transfer in a transformer is
modeled in this work using the Navier-Stokes equations
for incompressible flow, and the conservation of energy
equation. The mathematical mode1 used in the thesis
consists of four equations: energy conservation,
momentum conservation, and mass conservation. The
solution of the energy equation produces the temperature
field, and the momentum equations determine the
velocities in the fluid. The mass conservation equation
ensures that fluid entering a control volume also leaves
the control volume and is used as the constraint on
pressure. The energy conservation equation is given by
Equation (1). The first term on the left hand side of the
energy conservation equation represents the energy
storage. The second and third terms represent the
advection of energy by the moving fluid. On the right
hand side of the equation, the first three terms are the
energy diffusion term and the last term represents the
energy generation per unit volume.
‘Cp ∂)/∂t (ρT) +Cp ∂/∂x (ρUT)+Cp ∂/∂y (ρVT)+Cp ∂/∂z
(ρWT)=∂/∂x Kx ∂T/∂x+∂/∂y Ky ∂T/∂y+∂/∂z Kz ∂T/∂z+Q'
(1)
The momentum conservation equations in three
dimensions, Equations (2) (3), (4) are used to calculate
the velocity fields. The first term in each equation
represents the change in momentum over the time. The
second, third and fourth terms on the left hand side of the
equations represent the advection of momentum. The first
three terms on the right-hand side of the equations
account for the net viscous forces, and the fourth term
represents the pressure forces. The last term of the y
direction momentum equation represents the buoyancy
force used when solving a natural convection problem.
∂/∂t (ρU) +∂/∂x (ρUU) +∂/∂y (ρVU)+∂/∂z (ρWU)=∂/∂x μ
∂U/∂x+∂/∂y μ ∂U/∂y+∂/∂z μ ∂U/∂z-∂P/∂x (2)
∂/∂t (ρV) +∂/∂x (ρUV) +∂/∂y (ρVV)+∂/∂z (ρWV)=∂/∂x μ
∂V/∂x+∂/∂y μ ∂V/∂y+∂/∂z μ ∂W/∂z-∂P/∂y+ρ∞βg(T-T∞)
(3)
∂/∂t (ρW)+∂/∂x (ρUW)+∂/∂y (ρVW)+∂/∂z (ρWW)=∂/∂x
μ ∂W/∂x+∂/∂y μ ∂W/∂y+∂/∂z μ ∂W/∂z-∂P/∂z (4)
Natural convection is the body force driving fluid flow
within a naturally oil cooled transformer. A buoyancy
force is the net effect of body forces acting on a fluid in
which there are density gradients. For this model, the
density gradient is induced by a temperature gradient in
the fluid, and the body force is due to the gravitational
field, g, acting in the negative x direction.
The buoyancy force in the momentum equation is
modeled by using the Boussinesq approximation .In that
term, ρ_∞, is the average fluid density, β is the thermal
coefficient of volume expansion, and T_∞, is the average
fluid temperature. Equation (5) is the continuity equation.
In that equation the first term accounts for the mass
storage, and the other three terms describe the change of
mass flow in both x, y and z directions, respectively.
( ∂)/∂t (ρ) +∂/∂x (ρU) +∂/∂y (ρV) +∂/∂z (ρW) =0 (5)
The mathematical model consists of a set of differential
equations expressing conservation of mass, momentum,
and energy, over a Cartesian domain. The fluid was
assumed to have Newtonian and laminar –Turbulent flow
characteristics. The energy equation was modified to
allow for conjugate heat transfer between a solid and the
surrounding fluid. A method for modeling the windings
as a homogeneous material was also introduced. The
transport equations were discretized using a finite volume
3. International Journal of Advanced Engineering, Management and Science (IJAEMS) [Vol-3, Issue-2, Feb- 2017]
https://dx.doi.org/10.24001/ijaems.3.2.23 ISSN : 2454-1311
www.ijaems.com Page | 143
approach, and the pressure-velocity coupling was handled
using the SIMPLE algorithm.
3.1 CFD analysis using Ansys Fluent
Fig 1: General process of CFD analysis
3.1.1Preprocessing & Solver set up
Geometry considered for analysis is that of an ONAN
distribution transformer (oil natural air natural).Model
contains a source, oil tank, cooling transformer oil, oil
collecting region and cooling tubes or radiators. Source
includes copper windings and coil. Major heat is
dissipated from the source due to eddy current loss and
copper loss and heat transfer occur due to convection,
conduction and radiation.
As Transformer is oil immersed to provide cooling by
natural convection, major heat transfer is occurred by
convection, so heat transfer by conduction and radiation is
negligible and neglected from Analysis. Geometry is
created using CatiaV5 R20.
Meshing is done in ANSYS ICEM CFD, with minimum
skewness of 0.82 .Maximum face size is 6mm and
maximum size is 12mm. Minimum edge length is 2mm.
Meshing is defined as discretizing the cad model into
finite element model. Simulation is done in Ansys
Fluent .Before 2006 Fluent is a separate solver, now
Ansys acquired Fluent and is within the Ansys workbench
module .Open the Setup option of Ansys fluent project
• Select Solver setup > General > among solver settings
choose the pressure based solver. CFD fluent consist of
two solvers for solving the CFD process i.e. pressure
based and density based. Here we choose pressure based;
this is because the fluid is incompressible. Choose the
velocity formulation as absolute and time option as steady
state. This is because flow is considered to have constant
properties with respect to time.
Select Solver setup > Models > Choose energy
equation on.. To solve the heat transfer problems the basic
energy equation has to be used and this can be used by
switching on the energy equation. Transition K-KL-
omega model is one of the most commonly used
turbulence models to model Transition flow. It is a three
equation model that means, it includes three extra
transport equations to represent the turbulent properties of
flow. The K-KL-omega transition model is used to
predict boundary layer development and calculate
transition onset. This model can be used to effectively
address the transition of the boundary layer from a
laminar to a turbulent regime. The K - KL -omega
model is considered to be a three-equation eddy-viscosity
type, which includes transport equations for turbulent
kinetic energy (K_T), laminar kinetic energy (K_L), and
the inverse turbulent time scale (ω).
Fig 2: Catia model used in the analysis
4. International Journal of Advanced Engineering, Management and Science (IJAEMS) [Vol-3, Issue-2, Feb- 2017]
https://dx.doi.org/10.24001/ijaems.3.2.23 ISSN : 2454-1311
www.ijaems.com Page | 144
Fig 3: Meshed model
Select Cell zone conditions and choose the appropriate
materials for the zones. Transformer oil is defined to fluid
zone. Copper is assigned to part-source and in source
terms Energy source of 1302082 w/m^3 is defined to
represent energy generation in core. In part- porous
domain switch on the porous zone to model
corresponding case if not uncheck the option. In the
solution method choose pressure velocity coupling
scheme as SIMPLE.
SIMPLE is the acronym of semi implicit method for
pressure linked equations. It is the default scheme and the
robust one which can be used for all types of analysis.
Choose the gradient option as ‘least square cell based’. It
is the default method; has the good accuracy and the same
time it is computationally less intensive. Choose body
force weighted option for the pressure. It is used for
gravity has prominent role. Choose momentum, turbulent
kinetic energy and laminar kinetic energy and specific
dissipation rate and energy as first order upwind.
Select the monitors > residuals. Click edit. In the dialogue
box that appears edit the convergence criteria of
continuity, x velocity, y velocity, z velocity, k, Omega as
0.001. Energy as 0.000001 Close the dialogue box.
In the solution initialization select the hybrid initialization
and click initialize. By starting CFD simulation we must
provide fluent with an initial guess for the solution flow
field. Hybrid initialization is a collection of recipes and
boundary interpolation methods. It solves Laplace's
equation to determine the velocity and pressure fields. All
other variables, such as temperature, turbulence, species
fractions, volume fractions, etc., will be automatically
patched based on domain averaged values or a particular
interpolation recipe. In the Run calculation window edit
the number of iterations as 10000 and click calculate.
Within 500 iterations solver will give the converged
results with required accuracy.
Table.1: Material properties used
Table 2: Boundary conditions
5. International Journal of Advanced Engineering, Management and Science (IJAEMS) [Vol-3, Issue-2, Feb- 2017]
https://dx.doi.org/10.24001/ijaems.3.2.23 ISSN : 2454-1311
www.ijaems.com Page | 145
3.1.2 Postprocessing
Fig.4: Geometry of different cases used in the analysis
IV. RESULTS AND OBSERVATIONS
Table.3: Values of output variables for all cases
4.1 Temperature contours
Fig: 5: Temperature contour for all 5 cases
4.2 Graph comparing Results
Fig.6.Graph showing max temperature vs all cases
Fig.7: Graph showing turbulence kinetic energy vs all
cases
6. International Journal of Advanced Engineering, Management and Science (IJAEMS) [Vol-3, Issue-2, Feb- 2017]
https://dx.doi.org/10.24001/ijaems.3.2.23 ISSN : 2454-1311
www.ijaems.com Page | 146
Fig.8: Graph comparing different velocities
V. CONCLUSION
Numerical simulation of free convection in onan
distribution transformer is done and a mixed laminar and
turbulent flow is found to be occurred, also design
modification in cooling tubes provides better turbulent
generation and increased heat transfer. Cooling tube with
axial grooves and fins are found to be most effective by
decreasing hot spot temperature by 34 degree Celsius
.Also from the simulation it is found that natural
convection flow of transfer oil due to density difference
with increase in temperature can be effectively simulated
using computational fluid dynamics. .
Fig.9: Graph comparing Turbulence eddy frequency vs
cases
REFERENCES
[1] International Journal of Emerging Technology and
Advanced Engineering ISSN 2250-2459, ISO
9001:2008 Certified Journal, Volume 4, Issue 3,
March 2014) 253Experimental Study of Free
Convection Heat Transfer From Array Of Vertical
Tubes At Different Inclinations by
A.Satyanarayana.Reddy, Suresh Akella, AMK.
Prasad
[2] Vol. 3 Issue 4, April – 2014 International Journal of
Engineering Research & Technology (IJERT) ISSN:
2278-0181 Investigation of the Temperature
Variation in Distribution Transformer Cooling
System by A.Satyanarayana.Reddy, Suresh Akella,
AMK. Prasad
[3] Thermal Modeling of a Natural-Convection-Cooled,
Oil-Immersed Distribution Transformer by Robert
Michael Marko.
[4] Ştefan D.L. ŢĂLU1, Mihai D.L. ŢĂLU2-
Dimensional optimization of frontal radiators Of
cooling system for power transformer 630 Kva
20/0.4 kv in terms of maximum heat transfer, U.P.B.
Sci. Bull. Series C, Vol. 72, Iss. 4, 2010
[5] Miguel E. Rosillo, Carlos A. Herrera, and Guillermo
Jaramillo, IEEE Transactions On Power Delivery,
Vol. 27, No. 4, October 2012
[6] Y. X. Wang, H. B. Ma and G. P. Peterson
Investigation of the Temperature Distribution on
Radiator Fins with Micro Heat Pipes, Journal Of
Thermo physics And Heat Transfer ,Vol. 15, No. 1,
January–March 2001
[7] S. A. Nada a and M. Mowad, Free convection from
a vertical and inclined semicircular cylinder.