This document outlines boundary conditions, turbulence models, and other setup considerations for computational fluid dynamics (CFD) simulations of incompressible flows using ANSYS Fluent. It discusses inlet and outlet boundary conditions such as velocity inlet, pressure inlet, outflow, and others. It also covers turbulence modeling requirements, specifying other boundary conditions like walls, and defining fluid, solid, and porous zones. Setup of the solver, models, and determining convergence are outlined to provide the key steps for setting up an incompressible flow problem in Fluent.
Flow Inside a Pipe with Fluent Modelling Andi Firdaus
This document describes a numerical simulation of laminar and turbulent flow inside a pipe using Fluent software. The simulation models water flow inside a 1m diameter pipe that is 20m long. Two models are considered: laminar flow at a Reynolds number of 300 and turbulent flow at 8500. Theoretical equations for laminar and turbulent velocity profiles, entrance length, and Reynolds number correlations are presented. The numerical simulation sets up the models with appropriate boundary and material properties to solve the steady-state Navier-Stokes equations and compare results to experimental data.
This document discusses hydraulic losses that occur in pipes due to fluid viscosity. It introduces the Darcy-Weisbach equation and Moody chart for calculating friction factor based on Reynolds number and relative roughness. Minor losses from fittings are also addressed using loss coefficients. Examples are provided to demonstrate calculating head loss, pressure drop, flow rate, and pipe sizing for given system parameters. Key aspects covered include laminar and turbulent flow regimes, friction factor dependence on Reynolds number and roughness, and accounting for losses across full pipe systems.
This document describes how to develop a Microsoft Excel program to aid in sizing and selecting centrifugal pumps for process pumping needs. It outlines the basic model, applicable equations including Bernoulli's equation and Darcy's equation for pressure loss. It also discusses parameters like Reynolds number, friction factor, pipe roughness, and provides the Colebrook equation for calculating friction factor. The document recommends using Excel's Solver tool to iteratively solve the Colebrook equation by setting the friction factor as the target cell and constraints.
Design & Computational Fluid Dynamics Analyses of an Axisymmetric Nozzle at T...IRJET Journal
This document summarizes a numerical investigation of flow through an axisymmetric boat tail nozzle at transonic conditions using computational fluid dynamics (CFD). The study analyzed the effects of friction on adiabatic flow and determined a friction factor of 0.001452. CFD simulations using GAMBIT and FLUENT were conducted with a k-epsilon turbulence model to analyze pressure distributions, velocity vectors, and coefficient of pressure plots. Validation against experimental data showed reasonable agreement. The study concluded that CFD can predict nozzle aerodynamics, though turbulence models under predict pressures. Friction was found to impact real flows compared to isentropic assumptions. Future work could analyze shockwaves at Mach 0.8.
Diffusers are extensively used in centrifugal
compressors, axial flow compressors, ram jets, combustion
chambers, inlet portions of jet engines and etc. A small change in
pressure recovery can increases the efficiency significantly.
Therefore diffusers are absolutely essential for good turbo
machinery performance. The geometric limitations in aircraft
applications where the diffusers need to be specially designed so
as to achieve maximum pressure recovery and avoiding flow
separation.
The study behind the investigation of flow separation in a planar
diffuser by varying the diffuser taper angle for axisymmetric
expansion. Numerical solution of 2D axisymmetric diffuser model
is validated for skin friction coefficient and pressure coefficient
along upper and bottom wall surfaces with the experimental
results of planar diffuser predicted by Vance Dippold and
Nicholas J. Georgiadis in NASA research center [2]
.
Further the diffuser taper angle is varied for other different
angles and results shows the effect of flow separation were it is
reduces i.e., for what angle and at which angle it is just avoided.
This project investigates fluid flow near a flat plate that is suddenly accelerated. The velocity profile is obtained using the similarity method proposed by Stokes, which reduces the partial differential equations to an ordinary differential equation. The equation is solved numerically using Simpson's approximation. The results show that the velocity profiles for varying times are similar when scaled appropriately. The velocity and shear stress at the wall are also examined for different times. The shear stress decreases with increasing time as diffusion causes the flow to develop.
1. The document discusses various concepts related to fluid mechanics including pressure, Pascal's law, units of pressure, measurement of pressure using manometers, and example problems. It provides definitions and equations for pressure, hydrostatic pressure, Pascal's law, and discusses different types of manometers and pressure gauges for measuring pressure. Example problems are included for calculating pressure under various conditions.
This document discusses fluid dynamics and flow through pipes. It defines types of flow such as steady, uniform, laminar and turbulent. It also defines concepts like discharge, mass flow rate, and the continuity equation. Examples are provided to demonstrate how to use the continuity equation to calculate velocities and flow rates at different points in pipes with changes in diameter or branches.
Flow Inside a Pipe with Fluent Modelling Andi Firdaus
This document describes a numerical simulation of laminar and turbulent flow inside a pipe using Fluent software. The simulation models water flow inside a 1m diameter pipe that is 20m long. Two models are considered: laminar flow at a Reynolds number of 300 and turbulent flow at 8500. Theoretical equations for laminar and turbulent velocity profiles, entrance length, and Reynolds number correlations are presented. The numerical simulation sets up the models with appropriate boundary and material properties to solve the steady-state Navier-Stokes equations and compare results to experimental data.
This document discusses hydraulic losses that occur in pipes due to fluid viscosity. It introduces the Darcy-Weisbach equation and Moody chart for calculating friction factor based on Reynolds number and relative roughness. Minor losses from fittings are also addressed using loss coefficients. Examples are provided to demonstrate calculating head loss, pressure drop, flow rate, and pipe sizing for given system parameters. Key aspects covered include laminar and turbulent flow regimes, friction factor dependence on Reynolds number and roughness, and accounting for losses across full pipe systems.
This document describes how to develop a Microsoft Excel program to aid in sizing and selecting centrifugal pumps for process pumping needs. It outlines the basic model, applicable equations including Bernoulli's equation and Darcy's equation for pressure loss. It also discusses parameters like Reynolds number, friction factor, pipe roughness, and provides the Colebrook equation for calculating friction factor. The document recommends using Excel's Solver tool to iteratively solve the Colebrook equation by setting the friction factor as the target cell and constraints.
Design & Computational Fluid Dynamics Analyses of an Axisymmetric Nozzle at T...IRJET Journal
This document summarizes a numerical investigation of flow through an axisymmetric boat tail nozzle at transonic conditions using computational fluid dynamics (CFD). The study analyzed the effects of friction on adiabatic flow and determined a friction factor of 0.001452. CFD simulations using GAMBIT and FLUENT were conducted with a k-epsilon turbulence model to analyze pressure distributions, velocity vectors, and coefficient of pressure plots. Validation against experimental data showed reasonable agreement. The study concluded that CFD can predict nozzle aerodynamics, though turbulence models under predict pressures. Friction was found to impact real flows compared to isentropic assumptions. Future work could analyze shockwaves at Mach 0.8.
Diffusers are extensively used in centrifugal
compressors, axial flow compressors, ram jets, combustion
chambers, inlet portions of jet engines and etc. A small change in
pressure recovery can increases the efficiency significantly.
Therefore diffusers are absolutely essential for good turbo
machinery performance. The geometric limitations in aircraft
applications where the diffusers need to be specially designed so
as to achieve maximum pressure recovery and avoiding flow
separation.
The study behind the investigation of flow separation in a planar
diffuser by varying the diffuser taper angle for axisymmetric
expansion. Numerical solution of 2D axisymmetric diffuser model
is validated for skin friction coefficient and pressure coefficient
along upper and bottom wall surfaces with the experimental
results of planar diffuser predicted by Vance Dippold and
Nicholas J. Georgiadis in NASA research center [2]
.
Further the diffuser taper angle is varied for other different
angles and results shows the effect of flow separation were it is
reduces i.e., for what angle and at which angle it is just avoided.
This project investigates fluid flow near a flat plate that is suddenly accelerated. The velocity profile is obtained using the similarity method proposed by Stokes, which reduces the partial differential equations to an ordinary differential equation. The equation is solved numerically using Simpson's approximation. The results show that the velocity profiles for varying times are similar when scaled appropriately. The velocity and shear stress at the wall are also examined for different times. The shear stress decreases with increasing time as diffusion causes the flow to develop.
1. The document discusses various concepts related to fluid mechanics including pressure, Pascal's law, units of pressure, measurement of pressure using manometers, and example problems. It provides definitions and equations for pressure, hydrostatic pressure, Pascal's law, and discusses different types of manometers and pressure gauges for measuring pressure. Example problems are included for calculating pressure under various conditions.
This document discusses fluid dynamics and flow through pipes. It defines types of flow such as steady, uniform, laminar and turbulent. It also defines concepts like discharge, mass flow rate, and the continuity equation. Examples are provided to demonstrate how to use the continuity equation to calculate velocities and flow rates at different points in pipes with changes in diameter or branches.
1. As gas injection rate increases, the gravitational pressure drop decreases while the frictional pressure drop increases in an oil well.
2. Oil production rate increases when the decrease in gravitational pressure drop is greater than the increase in frictional pressure drop.
3. Oil production rate declines when the increase in frictional pressure drop is greater than the decrease in gravitational pressure drop.
Hydraulic analysis of complex piping systems (updated)Mohsin Siddique
1. Given: Pipe characteristics (D, L, e), fluid properties (ν), flow conditions (Q or V)
2. Calculate Reynold's number (Re) using the given flow parameters
3. Determine friction factor (f) from Moody diagram or equations based on Re and relative roughness (e/D)
4. Use Darcy-Weisbach equation to calculate head loss (hf) or solve for unknown parameter (Q or V)
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.
Here are the key steps to solve this problem:
1. Draw a schematic of the system and define the parameters. You have a pipe with water flowing through it at a rate of 0.15 kg/s. The inlet temperature is 20°C and desired outlet temperature is 50°C.
2. Write the energy balance equation:
Rate of heat transfer into the water = Rate of increase of thermal energy of water
Q = mCpΔT
Where:
Q = Rate of heat transfer (W)
m = Mass flow rate (0.15 kg/s)
Cp = Specific heat of water (4.18 kJ/kg-K)
ΔT = Increase in
International Journal of Mathematics and Statistics Invention (IJMSI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJMSI publishes research articles and reviews within the whole field Mathematics and Statistics, 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.
This document summarizes key topics in fluid statics covered in Lecture 3 of Fundamentals of Fluid Mechanics, including the basic equations of fluid statics, pressure variation in static fluids, hydrostatic force on submerged surfaces, and buoyancy. It discusses concepts such as Pascal's law, pressure-height relationships, and calculating forces on plane and curved surfaces. Examples are provided for calculating pressures, forces, and buoyant forces in various fluid static scenarios.
This document discusses wellbore performance and flow modeling. It covers:
1) Single phase liquid, gas, and two phase flow models based on mechanical energy balance equations. Pressure drops are calculated considering elevation change, kinetic energy, and friction.
2) Methods for calculating friction factors including Fanning, Darcy, and Moody charts. Correlations for gas properties like viscosity and deviation factor are also presented.
3) Examples of calculating pressure drops in single phase liquid and gas flows. Numerical methods for solving gas flow equations are described.
4) Multiphase flow is more complex due to different flow regimes affecting pressure gradients. Models include homogeneous and separated flow approaches.
This presentation was created to provide a quick refresher to single-phase fluid flow line sizing. The content of this presentation was obtained from various literature (handbooks and website).
Please provide your comments
The document contains examples and solutions for fluid mechanics problems involving pressure, manometers, forces on submerged surfaces, and dams.
1) It calculates gauge and absolute pressures at various depths, pressures for different liquids in manometers, and forces on inclined and triangular planes.
2) It determines beam positions in a dock gate to evenly distribute load, the torque to close a butterfly valve, and the load and point of action on a curved dam face.
The document discusses hydrostatic forces on surfaces submerged in fluids. It defines fluid statics as dealing with fluids at rest, where the only stress is normal stress due to pressure variations from fluid weight. It describes how to calculate the resultant force and center of pressure on plane and curved surfaces for non-uniform pressure distributions. For a rectangular plate, the resultant force is the pressure at the centroid multiplied by the area, and the center of pressure is below the centroid. Examples are provided to demonstrate calculating these values.
110207 Fan Testing at Malabar Odor Control Site SydneyRoy Singh
Fan performance tests were conducted on six large odor control scrubber fans at the Malabar Sewerage Treatment Plant in Sydney. Tests were required to determine if the fans could perform adequately at higher operating points after planned upgrades. In-situ tests were performed since constructing a large temporary test rig was not feasible. Lessons learned included understanding differences between total static pressure and differential pressure fan curves, and accounting for increased unbalance in overhung fan configurations. The tests provided performance data that could be compared to manufacturer curves and used to inform upgrade decisions.
The document summarizes numerical simulations of the flow inside a centrifugal compressor's vaneless diffuser and volute. Gambit was used to generate meshes of the geometries, and Fluent was used to simulate the flows. Results from simulations at different speeds and mass flows agreed well with experimental data. The simulations showed separated flow on the diffuser hub wall at low mass flows. Inside the volute, swirling flow structures like vortices were observed. The tongue region caused static pressure distortions that affected the flow.
The document discusses fluid pressure and its relationship to depth. It introduces Pascal's law and how it applies to hydraulic systems. Specifically:
1) Pressure increases with depth in fluids due to the weight of the fluid above pushing down. Pascal's law states that pressure increases are equal throughout a confined fluid.
2) Hydraulic systems use this principle to multiply forces. A small force applied to a piston with a small surface area can create a much larger force when transmitted through fluid to a piston with a larger surface area.
3) An example is given of a hydraulic car lift, where 1 kg applied to a small piston creates enough pressure to lift 10 kg with a larger piston, multiplying the applied
The document discusses pressure drop analysis in heat exchangers. It states that the pressure drop in a heat exchanger is essential to determine as it is proportional to the pumping power required. It also directly relates to factors like heat transfer, operation, size and cost of the heat exchanger. The document then goes on to describe methods for calculating pressure drop due to friction and other contributions in different types of heat exchangers like extended surface and plate heat exchangers. Key equations for determining pressure drop from friction, flow acceleration/deceleration and other sources are also presented.
1) The document discusses fluid mechanics concepts related to pressure and fluid statics. It covers topics like pressure measurement devices, hydrostatic forces on submerged surfaces, buoyancy, stability of floating and immersed bodies, and fluids in rigid-body motion.
2) Key concepts covered include how pressure varies with depth in fluids, Pascal's law, Archimedes' principle of buoyancy, stability criteria for floating and immersed objects, and how pressure varies in fluids undergoing linear or rotational acceleration.
3) Various pressure measurement devices are described, including manometers, bourdon tubes, and deadweight testers. Equations are provided for calculating hydrostatic forces on plane and curved surfaces.
Chapter 3 static forces on surfaces [compatibility mode]imshahbaz
1) The document discusses forces on submerged surfaces due to static fluids, including calculating hydrostatic pressures and determining the resultant force and center of pressure.
2) It provides methods for calculating the resultant force on plane and curved surfaces, including using pressure diagrams which graphically represent pressure changes with depth.
3) Examples are given for determining pressures, resultant forces, and centers of pressure on surfaces like vertical walls and combinations of liquids in tanks.
The document provides an overview of hydrostatics. It defines key properties of liquids like viscosity, bulk modulus, and density. It describes how pressure increases with depth in liquids and defines concepts like gauge pressure, absolute pressure, and pressure head. Archimedes' principle states that the upward force on a submerged object equals the weight of the fluid displaced. Worked examples demonstrate calculating pressure, force, and volume displaced for various hydrostatic situations.
The document discusses energy losses in pipeline systems. It covers topics such as velocity profiles in pipes, sources of energy loss including shock losses at enlargements and contractions, friction losses, and examples of calculating losses. Bernoulli's equation is applied to analyze pressure and velocity changes between points along pipelines. Key sources of loss are friction against pipe walls and shocks caused by changes in pipe diameter.
This document discusses multiphase flow theory and key concepts. It begins by presenting the pressure drop equation for single-phase and two-phase flows. Key parameters that influence flow patterns like surface tension and gravity are described. Common flow regimes in vertical heated tubes are discussed along with how properties vary radially and change along the tube axis. Common terminology used in multiphase flows like phase fraction, velocity, and area are defined. Advanced relationships involving drift velocity and flux are also presented.
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
Numerical analysis for two phase flow distribution headers in heat exchangerseSAT Journals
Abstract A flow header having number of multiple small branch pipes are commonly used in heat exchangers and boilers. In beginning the headers were designed based on the assumption that the fluid distribute equally to all lateral pipes. In practical situation the flow is not uniform and equal in all lateral pipes. Mal distribution of flow in heat exchangers significantly affects their performance. Non-uniform flow distribution from header to the branch pipes in a flow system will lead to 25% decrease in effectiveness of a cross flow heat exchanger. Mal distribution of flow in the header is influenced by the geometric parameters and operating conditions of the header. In this work the flow distribution among the branch pipes of dividing flow header system is analyzed for two phase flow condition. In the two phase flow condition, the effect of change in geometric cross sectional shape of the header (circular, square), inlet flow velocities are varied to find the flow mal distribution through the lateral pipes are investigated with the use of Computational Fluid Dynamics software. Keywords: circular, square headers and Computational Fluid Dynamics software. (CFD)
The document outlines a 14-step process for manually designing a shell and tube heat exchanger using the Kern method. Key steps include: 1) obtaining thermo-physical properties of fluids, 2) performing an energy balance to determine heat duty, 3) assuming an overall heat transfer coefficient, 4) deciding tube passes and calculating the log mean temperature difference, 5) calculating required heat transfer area, 6) selecting tube materials and dimensions, 7) deciding exchanger type and tube pitch, 8) assigning fluids and selecting baffles, 9) calculating heat transfer coefficients, 10) checking the calculated overall heat transfer coefficient, 11) recalculating as needed, 12) calculating overdesign, 13) calculating pressure drops, and 14)
1. As gas injection rate increases, the gravitational pressure drop decreases while the frictional pressure drop increases in an oil well.
2. Oil production rate increases when the decrease in gravitational pressure drop is greater than the increase in frictional pressure drop.
3. Oil production rate declines when the increase in frictional pressure drop is greater than the decrease in gravitational pressure drop.
Hydraulic analysis of complex piping systems (updated)Mohsin Siddique
1. Given: Pipe characteristics (D, L, e), fluid properties (ν), flow conditions (Q or V)
2. Calculate Reynold's number (Re) using the given flow parameters
3. Determine friction factor (f) from Moody diagram or equations based on Re and relative roughness (e/D)
4. Use Darcy-Weisbach equation to calculate head loss (hf) or solve for unknown parameter (Q or V)
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.
Here are the key steps to solve this problem:
1. Draw a schematic of the system and define the parameters. You have a pipe with water flowing through it at a rate of 0.15 kg/s. The inlet temperature is 20°C and desired outlet temperature is 50°C.
2. Write the energy balance equation:
Rate of heat transfer into the water = Rate of increase of thermal energy of water
Q = mCpΔT
Where:
Q = Rate of heat transfer (W)
m = Mass flow rate (0.15 kg/s)
Cp = Specific heat of water (4.18 kJ/kg-K)
ΔT = Increase in
International Journal of Mathematics and Statistics Invention (IJMSI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJMSI publishes research articles and reviews within the whole field Mathematics and Statistics, 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.
This document summarizes key topics in fluid statics covered in Lecture 3 of Fundamentals of Fluid Mechanics, including the basic equations of fluid statics, pressure variation in static fluids, hydrostatic force on submerged surfaces, and buoyancy. It discusses concepts such as Pascal's law, pressure-height relationships, and calculating forces on plane and curved surfaces. Examples are provided for calculating pressures, forces, and buoyant forces in various fluid static scenarios.
This document discusses wellbore performance and flow modeling. It covers:
1) Single phase liquid, gas, and two phase flow models based on mechanical energy balance equations. Pressure drops are calculated considering elevation change, kinetic energy, and friction.
2) Methods for calculating friction factors including Fanning, Darcy, and Moody charts. Correlations for gas properties like viscosity and deviation factor are also presented.
3) Examples of calculating pressure drops in single phase liquid and gas flows. Numerical methods for solving gas flow equations are described.
4) Multiphase flow is more complex due to different flow regimes affecting pressure gradients. Models include homogeneous and separated flow approaches.
This presentation was created to provide a quick refresher to single-phase fluid flow line sizing. The content of this presentation was obtained from various literature (handbooks and website).
Please provide your comments
The document contains examples and solutions for fluid mechanics problems involving pressure, manometers, forces on submerged surfaces, and dams.
1) It calculates gauge and absolute pressures at various depths, pressures for different liquids in manometers, and forces on inclined and triangular planes.
2) It determines beam positions in a dock gate to evenly distribute load, the torque to close a butterfly valve, and the load and point of action on a curved dam face.
The document discusses hydrostatic forces on surfaces submerged in fluids. It defines fluid statics as dealing with fluids at rest, where the only stress is normal stress due to pressure variations from fluid weight. It describes how to calculate the resultant force and center of pressure on plane and curved surfaces for non-uniform pressure distributions. For a rectangular plate, the resultant force is the pressure at the centroid multiplied by the area, and the center of pressure is below the centroid. Examples are provided to demonstrate calculating these values.
110207 Fan Testing at Malabar Odor Control Site SydneyRoy Singh
Fan performance tests were conducted on six large odor control scrubber fans at the Malabar Sewerage Treatment Plant in Sydney. Tests were required to determine if the fans could perform adequately at higher operating points after planned upgrades. In-situ tests were performed since constructing a large temporary test rig was not feasible. Lessons learned included understanding differences between total static pressure and differential pressure fan curves, and accounting for increased unbalance in overhung fan configurations. The tests provided performance data that could be compared to manufacturer curves and used to inform upgrade decisions.
The document summarizes numerical simulations of the flow inside a centrifugal compressor's vaneless diffuser and volute. Gambit was used to generate meshes of the geometries, and Fluent was used to simulate the flows. Results from simulations at different speeds and mass flows agreed well with experimental data. The simulations showed separated flow on the diffuser hub wall at low mass flows. Inside the volute, swirling flow structures like vortices were observed. The tongue region caused static pressure distortions that affected the flow.
The document discusses fluid pressure and its relationship to depth. It introduces Pascal's law and how it applies to hydraulic systems. Specifically:
1) Pressure increases with depth in fluids due to the weight of the fluid above pushing down. Pascal's law states that pressure increases are equal throughout a confined fluid.
2) Hydraulic systems use this principle to multiply forces. A small force applied to a piston with a small surface area can create a much larger force when transmitted through fluid to a piston with a larger surface area.
3) An example is given of a hydraulic car lift, where 1 kg applied to a small piston creates enough pressure to lift 10 kg with a larger piston, multiplying the applied
The document discusses pressure drop analysis in heat exchangers. It states that the pressure drop in a heat exchanger is essential to determine as it is proportional to the pumping power required. It also directly relates to factors like heat transfer, operation, size and cost of the heat exchanger. The document then goes on to describe methods for calculating pressure drop due to friction and other contributions in different types of heat exchangers like extended surface and plate heat exchangers. Key equations for determining pressure drop from friction, flow acceleration/deceleration and other sources are also presented.
1) The document discusses fluid mechanics concepts related to pressure and fluid statics. It covers topics like pressure measurement devices, hydrostatic forces on submerged surfaces, buoyancy, stability of floating and immersed bodies, and fluids in rigid-body motion.
2) Key concepts covered include how pressure varies with depth in fluids, Pascal's law, Archimedes' principle of buoyancy, stability criteria for floating and immersed objects, and how pressure varies in fluids undergoing linear or rotational acceleration.
3) Various pressure measurement devices are described, including manometers, bourdon tubes, and deadweight testers. Equations are provided for calculating hydrostatic forces on plane and curved surfaces.
Chapter 3 static forces on surfaces [compatibility mode]imshahbaz
1) The document discusses forces on submerged surfaces due to static fluids, including calculating hydrostatic pressures and determining the resultant force and center of pressure.
2) It provides methods for calculating the resultant force on plane and curved surfaces, including using pressure diagrams which graphically represent pressure changes with depth.
3) Examples are given for determining pressures, resultant forces, and centers of pressure on surfaces like vertical walls and combinations of liquids in tanks.
The document provides an overview of hydrostatics. It defines key properties of liquids like viscosity, bulk modulus, and density. It describes how pressure increases with depth in liquids and defines concepts like gauge pressure, absolute pressure, and pressure head. Archimedes' principle states that the upward force on a submerged object equals the weight of the fluid displaced. Worked examples demonstrate calculating pressure, force, and volume displaced for various hydrostatic situations.
The document discusses energy losses in pipeline systems. It covers topics such as velocity profiles in pipes, sources of energy loss including shock losses at enlargements and contractions, friction losses, and examples of calculating losses. Bernoulli's equation is applied to analyze pressure and velocity changes between points along pipelines. Key sources of loss are friction against pipe walls and shocks caused by changes in pipe diameter.
This document discusses multiphase flow theory and key concepts. It begins by presenting the pressure drop equation for single-phase and two-phase flows. Key parameters that influence flow patterns like surface tension and gravity are described. Common flow regimes in vertical heated tubes are discussed along with how properties vary radially and change along the tube axis. Common terminology used in multiphase flows like phase fraction, velocity, and area are defined. Advanced relationships involving drift velocity and flux are also presented.
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
Numerical analysis for two phase flow distribution headers in heat exchangerseSAT Journals
Abstract A flow header having number of multiple small branch pipes are commonly used in heat exchangers and boilers. In beginning the headers were designed based on the assumption that the fluid distribute equally to all lateral pipes. In practical situation the flow is not uniform and equal in all lateral pipes. Mal distribution of flow in heat exchangers significantly affects their performance. Non-uniform flow distribution from header to the branch pipes in a flow system will lead to 25% decrease in effectiveness of a cross flow heat exchanger. Mal distribution of flow in the header is influenced by the geometric parameters and operating conditions of the header. In this work the flow distribution among the branch pipes of dividing flow header system is analyzed for two phase flow condition. In the two phase flow condition, the effect of change in geometric cross sectional shape of the header (circular, square), inlet flow velocities are varied to find the flow mal distribution through the lateral pipes are investigated with the use of Computational Fluid Dynamics software. Keywords: circular, square headers and Computational Fluid Dynamics software. (CFD)
The document outlines a 14-step process for manually designing a shell and tube heat exchanger using the Kern method. Key steps include: 1) obtaining thermo-physical properties of fluids, 2) performing an energy balance to determine heat duty, 3) assuming an overall heat transfer coefficient, 4) deciding tube passes and calculating the log mean temperature difference, 5) calculating required heat transfer area, 6) selecting tube materials and dimensions, 7) deciding exchanger type and tube pitch, 8) assigning fluids and selecting baffles, 9) calculating heat transfer coefficients, 10) checking the calculated overall heat transfer coefficient, 11) recalculating as needed, 12) calculating overdesign, 13) calculating pressure drops, and 14)
This document provides instructions for using the WaterBudget component in the OMS 3 console to model the water budget and simulate discharge, actual evapotranspiration, runoff, and drainage for a given area. The component solves water budget equations using inputs of rainfall, potential evapotranspiration, and other parameters. It produces time series outputs of water storage, discharge, evapotranspiration, runoff, and drainage that can be used for hydrologic modeling and forecasting. Links are provided to download necessary files and access the component's source code.
Experimental Investigations and Computational Analysis on Subsonic Wind Tunnelijtsrd
This paper disclose the entire approach to design an open circuit subsonic wind tunnel which will be used to consider the wind impact on the airfoil. The current rules and discoveries of the past research works were sought after for plan figuring of different segments of the wind tunnel. Wind speed of 26 m s have been practiced at the test territory. The wind qualities over a symmetrical airfoil are viewed as probably in a low speed wind tunnel. Tests were finished by moving the approach, from 0 to 5 degree. The stream attributes over a symmetrical airfoil are examined tentatively. The pressure distribution on the airfoil area was estimated, lift and drag force were estimated and velocity profiles were acquired. Rishabh Kumar Sahu | Saurabh Sharma | Vivek Swaroop | Vishal Kumar ""Experimental Investigations and Computational Analysis on Subsonic Wind Tunnel"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23511.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23511/experimental-investigations-and-computational-analysis-on-subsonic-wind-tunnel/rishabh-kumar-sahu
Numerical assessment of the backward facing steps nozzleeSAT Journals
Abstract The backward facing steps nozzle (BFSN) is a flow adjustable exit area nozzle for large rocket engines. It consists of two parts, the first is a base nozzle with small area ratio and the second part is a nozzle extension with surface consists of backward facing steps. The number of steps and their heights are carefully chosen to produce controlled flow separation at steps edges that adjust the nozzle exit area at all altitudes (pressure ratios). The BFSN performance parameters are assessed in terms of thrust and side loads against the dual-bell nozzle (DBN) with the same pressure ratios and cross sectional areas. The DBN is a two-mode flow adjustable exit area nozzle for low and high altitude. Three-dimensional turbulent flow solutions are obtained for the BFSN indicating that the flow is axi-symmetric and does not generate significant side loads. Further confirmation of the axi-symmetric flow is obtained by comparing the three-dimensional flow with the two-dimensional axi-symmetric solutions. The comparison of the thrust generated over the PR range from 50 to 1500 shows that BFSN generates more uniform and higher thrust than the DBN in the intermediate pressure ratios. At PR 1500 (high altitude), the BFSN thrust is 0.28% less than the DBN. All numerical solutions are obtained using the Fluent code. Keywords: Backward facing steps nozzle, Turbulent flow in supersonic nozzle, Side load in supersonic nozzle.
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.
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A heat exchanger was simulated using Aspen Plus to heat Freon-12 from 240 K to 300 K using ethylene glycol at 350 K. The simulation specified the streams, calculated the heat transfer coefficients, determined the geometry of the exchanger including number of tubes, tube size and length, shell diameter, and baffles. The results of the simulation were examined to check if the design met the objectives of heating the Freon to the required temperature while maintaining a 10 K minimum approach and not exceeding pressure drop limits.
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.
This document describes different flow measurement devices including the venturi meter, orifice plate, and rotameter. It provides details on how each device works based on pressure differences caused by a flow restriction. The objectives are to study and compare the characteristics of venturi meters and orifice plates, calculate flow rates using measured pressure drops, and understand how rotameters operate based on the position of a float. An apparatus is described that can be used to collect pressure and flow rate data from each device to analyze flow measurement principles.
This document provides an overview of modeling piping networks in CHEMCAD software. It discusses how to use pressure nodes to specify known variables like pressures and calculate unknown variables like flowrates. Pressure nodes represent points where pressure changes and can be used to connect unit operations in a piping network. The flowrate and pressure options at each node are described to demonstrate how nodes can be used to properly constrain piping network calculations in CHEMCAD.
This document discusses modeling heat transfer in a tube heat exchanger using analytical and numerical methods. It will use MATLAB and FLUENT software to model the heat transfer process. Governing equations for the heat transfer and fluid flow are presented. Initial and boundary conditions are defined to solve the equations numerically using a 4th order Runge-Kutta method in MATLAB. The goal is to investigate the results from analytical, numerical and simulation approaches to optimize the heat exchanger efficiency.
The document summarizes the key objectives and methods of designing air conditioning duct systems. It discusses important requirements of ducts, general design rules, classification based on pressure and velocity, and commonly used design methods like the velocity method and equal friction method. The velocity method involves selecting velocities and calculating diameters and pressure drops. The equal friction method equalizes pressure drop per unit length across ducts. Both aim to optimize design to minimize costs while meeting airflow requirements.
5.good practice & hr imp activitiesRavi Shankar
The document provides guidance on good practices for collecting and maintaining important technical information about a power plant's equipment and operations. It recommends assembling a thermal kit from the turbine supplier with performance curves, as well as collecting heat balance diagrams, pump/fan curves, piping diagrams, specifications for heat exchangers and flow elements, and historical operating data. Maintaining this information in a centralized location helps engineers properly evaluate equipment performance and potential improvement projects.
This document describes an Open Modeling System (OMS) component for solving Richards' equation in one dimension to model water flow and transport in soil. The component uses a nested Newton algorithm to solve the nonlinear system of equations. Input data includes soil hydraulic properties, initial conditions, and boundary conditions. Output includes water pressure and water content profiles over time. Instructions are provided on running the component within the OMS console.
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Mechatronics is a multidisciplinary field that refers to the skill sets needed in the contemporary, advanced automated manufacturing industry. At the intersection of mechanics, electronics, and computing, mechatronics specialists create simpler, smarter systems. Mechatronics is an essential foundation for the expected growth in automation and manufacturing.
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The Rapid growth of technology and infrastructure has made our lives easier. The
advent of technology has also increased the traffic hazards and the road accidents take place
frequently which causes huge loss of life and property because of the poor emergency facilities.
Many lives could have been saved if emergency service could get accident information and
reach in time. Our project will provide an optimum solution to this draw back. A piezo electric
sensor can be used as a crash or rollover detector of the vehicle during and after a crash. With
signals from a piezo electric sensor, a severe accident can be recognized. According to this
project when a vehicle meets with an accident immediately piezo electric sensor will detect the
signal or if a car rolls over. Then with the help of GSM module and GPS module, the location
will be sent to the emergency contact. Then after conforming the location necessary action will
be taken. If the person meets with a small accident or if there is no serious threat to anyone’s
life, then the alert message can be terminated by the driver by a switch provided in order to
avoid wasting the valuable time of the medical rescue team.
Discover the latest insights on Data Driven Maintenance with our comprehensive webinar presentation. Learn about traditional maintenance challenges, the right approach to utilizing data, and the benefits of adopting a Data Driven Maintenance strategy. Explore real-world examples, industry best practices, and innovative solutions like FMECA and the D3M model. This presentation, led by expert Jules Oudmans, is essential for asset owners looking to optimize their maintenance processes and leverage digital technologies for improved efficiency and performance. Download now to stay ahead in the evolving maintenance landscape.
Generative AI Use cases applications solutions and implementation.pdfmahaffeycheryld
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https://www.leewayhertz.com/generative-ai-use-cases-and-applications/
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solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
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at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
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This document serves as a comprehensive step-by-step guide on how to effectively use PyCharm for remote debugging of the Windows Subsystem for Linux (WSL) on a local Windows machine. It meticulously outlines several critical steps in the process, starting with the crucial task of enabling permissions, followed by the installation and configuration of WSL.
The guide then proceeds to explain how to set up the SSH service within the WSL environment, an integral part of the process. Alongside this, it also provides detailed instructions on how to modify the inbound rules of the Windows firewall to facilitate the process, ensuring that there are no connectivity issues that could potentially hinder the debugging process.
The document further emphasizes on the importance of checking the connection between the Windows and WSL environments, providing instructions on how to ensure that the connection is optimal and ready for remote debugging.
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Use PyCharm for remote debugging of WSL on a Windo cf5c162d672e4e58b4dde5d797...
Fluent summary
1. BOUNDARY CONDITIONS FOR INCOMPRESSIBLE FLOW INLETS:
1. VELOCITY-INLET (7.3.4 of User's Guide): fixes incoming velocities
• Used for incompressible flows (similar to mass-flow inlet boundary condition that is used for
compressible flows to account for variable density)
• Pressure is calculated at the inlet
• For turbulent flows, also need to specify turbulence parameters
• For heat transfer, also need to specify inlet temperature
• For non-uniform velocity profile, use boundary profile file (7.6 of User's Guide) created from
previous simulation, analytical analysis, or experimental data.
Examples: uniform flow at inlet of pipe or duct, uniform flow for external flow, fully-developed
flow at inlet of pipe or duct
2. PRESSURE-INLET (7.3.3 of User's Guide): fixes total fluid pressure at inlet
• The total pressure, p0, is related to the static pressure, ps, through Bernoulli’s equation:
€
p0 = ps + 1
2
ρ
V
2
• Inlet flow velocity and static pressure are calculated
• Note that pressure is given as gage pressure with reference to Operating Pressure set in
Operating Conditions dialog box
Example: free boundary where there is flow in from a room at atmospheric pressure
3. INLET-VENT (7.3.6 of User's Guide): fixes ambient total pressure with inlet vent (assumed
infinitely thin) with specified loss coefficient, kL, that can be constant or a function of velocity
and is defined as
€
Δp = kL
1
2
ρ
V
2
• Similar to pressure inlet, except with a restriction at inlet
4. INTAKE-FAN (7.3.7 of User's Guide): fixes ambient total pressure with inlet fan (assumed
infinitely thin) with specified pressure jump that can be constant or a function of velocity
• Similar to pressure inlet, except with a pressure increase at inlet
2. BOUNDARY CONDITIONS FOR INCOMPRESSIBLE FLOW OUTLETS:
1. PRESSURE-OUTLET (7.3.8 of User's Guide): fixes static pressure at outlet
• Velocity at outlet is calculated
• Backflow conditions are specified to account for flow reversal (better convergence rate)
• Even if backflow is not expected in the final solution, values might be used during iteration
and should be realistic
2. OUTFLOW (7.3.11 of User's Guide): fixes exit as an outflow boundary
• Velocity and pressure are calculated
• Cannot be used with pressure inlet (problem is under-prescribed)
• Boundary conditions are the following:
1. Zero diffusion flux for all flow variables (true for fully-developed flow)
2. Overall mass balance correction
• For multiple outflow boundaries, the flow rate weighting (FRW) is used to set the percentage
of flow exiting each outlet:
€
% of flow through boundary =
FRWi
FRWi
i=1
Nbnd
∑
Example of where you must use pressure outlet instead of outflow:
3. OUTLET-VENT (7.3.12 of User's Guide): fixes ambient discharge pressure with outlet vent
(assumed infinitely fin) with specified loss coefficient, kL, that can be constant or function of
velocity and is defined as
€
Δp = kL
1
2
ρ
V
2
• Similar to pressure outlet, but with a restriction
4. EXHAUST-FAN: (7.3.13 of User's Guide) fixes ambient discharge pressure with exhaust fan
(assumed infinitely thin) with specified pressure jump that can be constant or function of velocity
• Similar to pressure outlet, but with a pressure jump
flow
pressure outlet outflow
3. TURBULENCE BOUNDARY CONDITIONS:
For the k-ε turbulence model there are two transport equations for k and ε that are 2nd
order in
space, thus need to specify two boundary conditions (at inlet and exit) for both k and ε.
1. Specify average turbulent kinetic energy (k) or turbulence intensity (I) defined as:
€
k =
3
2
ʹ′u( )2
and
€
I =
ʹ′u( )2
u
where typical range is 1% < I < 10%.
Ideally, use experimental data to measure k or I. For underdeveloped, undisturbed flow use
I = 1% (wind tunnel inlet or typical free stream air).
For fully-developed duct-flow use:
€
I = 0.16 ReDh
( )
−1/8
2. Specify turbulent dissipation rate (ε), turbulent length scale (
€
m ), viscosity ratio (µt/µ), or
hydraulic diameter (Dh):
To calculate ε from
€
m use the following:
€
ε = Cµ
3/ 4 k3/ 2
m
where
€
Cµ = 0.09
To calculate µt/µ from k and ε use the following:
€
µt
µ
= Cµ
ρ k2
ε µ
where
€
1<
µt
µ
<10
To calculate
€
m from Dh use the following:
€
m = 0.07 Dh
For turbulent flow around objects use:
€
m = 0.07 L, L = characteristic length scale
For boundary layers use:
€
m = 0.4 δ99,
€
δ99 = boundary layer thickness
For wind tunnels downstream of a wire mesh:
€
ε ≅
Δk U∞
L∞
€
Δk approximate decay of k
across domain (about 10%)
€
U∞ free-stream velocity
€
L∞ stream-wise domain length
NOTE: For turbulent heat transfer, specification of the turbulent Prandtl number controls the
turbulent heat transfer mixing and no additional boundary conditions are needed.
4. OTHER BOUNDARY CONDITIONS:
1. WALL (7.3.14 of User's Guide): fixes boundary as solid wall that bounds fluid regions
• By default, no-slip condition will be enforced
• Wall can be fixed or moving (translation or rotation)
• Can set the following thermal boundary conditions:
temperature, heat flux, convection, and/or external radiation
• Wall can have a finite thickness to model a thin layer between two zones. Can be used to
model a sheet of metal between fluid layers, a coating on a solid zone, contact resistance
between solid layers, or a thin wall with heat generation (for computer chips instead of
constant heat flux).
• For turbulent flows, can set the wall roughness by setting the Roughness Height, Ks,
(approximately the mean diameter of the roughness features) and the Roughness Constant,
Cs, which typically ranges from 0.5 to 1.0 and is hard to characterize. NOTE: Cell size should
be greater than the roughness height.
2. SYMMETRY (7.3.15 of User's Guide): fixes boundary as symmetry plane
• Used when both flow and thermal solution are symmetric about a plane to reduce
computational domain
• Use Display/Views menu and the Mirror Planes section to mirror the display
3. AXIS (7.3.17 of User's Guide): fixes boundary as axis for 2-D axisymmetric flow (use x-axis)
4. PERIODIC (7.3.16 of User's Guide): fixes boundary as periodic when geometry and flow
solution have a periodically repeating nature and will force the flow in to match the flow out
• Can have either (1) no pressure drop or (2) prescribed pressure drop
• Can specify either (1) translational or rotational periodicity
• Must link boundaries together as periodic: for FLUENT use Command Window and enter
"mesh/modify-zones/make-periodic" and select Periodic Conditions to set mass flow rate or
pressure gradient and upstream bulk temperature
Examples: flow through heat exchanger tube bundle and rotational with multiple fluid in ports
periodic
flow
periodic
symmetry
symmetry
flow
periodic
5. ZONES:
1. FLUID (7.2.1 of User's Guide): sets zone as fluid
• All active equations are solved
• Material properties must be set correctly
• Can define sources of heat, mass, momentum, turbulence, etc. within fluid zones
2. SOLID (7.2.2 of User's Guide): sets zone as solid
• Only the heat conduction equation is solved
• Material properties must be set correctly
Example: conduction through solid between heat exchanger passages
NOTE: In general, use the same edge (for 2-D)
or face (for 3-D) for the interface between
the fluid and the solid in ICEM so the mesh
nodes are the same at the fluid/solid interface.
In FLUENT, define the interface as coupled for
heat transfer across the interface. Alternatively,
you can use a non-conformal mesh.
3. POROUS MEDIA (7.2.3 of User's Guide): sets zone as porous media
• Examples of porous media include filters, packed beds, perforated plates, and tube banks
• Permeability and inertial losses for the porous media must be specified
• Heat transfer calculations assume thermal equilibrium between medium and fluid flow
• 1-D simplification of porous media model is POROUS JUMP (7.3.20 of User's Guide) for
thin membranes where pressure drop versus velocity must be specified
4. FAN (7.3.18 of User's Guide): lumped-parameter model used to determine the impact of a fan
with known characteristics (pressure rise and velocity profile at exit) upon a larger flow field
• The fan is assumed infinitely thin, thus is modeled as the interface between cells and the fan
zone type is an INTERFACE zone
5. RADIATOR (7.3.19 of User's Guide): lumped-parameter model used to add a heat exchange
element (for example a heat exchanger or condenser) with known characteristics (pressure drop
and heat transfer coefficient as a function of velocity) upon a larger flow field
• The radiator is assumed infinitely thin, thus is modeled as the interface between cells and the
radiator zone type is an INTERFACE zone
SOLID
FLUID
FLUID
6. FLUENT Summary: Outline for Model Setup
Below is a list of steps necessary to set up a convection problem in FLUENT. It only includes
the elements of FLUENT covered in ME 554. Additional models that were not covered in this
class (such as for deforming meshes, fluid structure interaction, multiphase flow, combustion,
etc. that are available in FLUENT) are not included in these steps.
1. Start FLUENT and choose: 2-D or 3-D, single precision or double precision
2. File/Read/Mesh: Import mesh into FLUENT from ICEM CFD (typically a .msh file).
3. Problem Setup
General
Mesh Check grid and verify that there are no negative volumes
Scale Change units or scale grid if necessary
Display Display mesh and visually verify mesh and boundary names
Solver
Type Select Pressure Based for pressure-correction equation derived
from conservation of mass for incompressible flow
Space For 2-D select Planar, Axisymmetric, or Axisymmetric Swirl
Time Select Steady or Transient
Units Define units for grid, properties, and calculated values
Models
Energy Turn on for conduction, convection, and compressible flow
Viscous
Model Select viscous model (inviscid, laminar, or one of the turbulence
models) based on Reynolds number for forced convection or
Rayleigh number for natural convection
k-ε Model Choose Standard for equilibrium flows; RNG or Realizable for
flows with high strain rates, swirl, rapidly changing pressures, or
separation
Near-Wall Use Standard-Wall Functions for equilibrium flows; Non-
Equilibrium Wall Functions or Enhanced Wall Functions for flows
with high strain rates, swirl, rapidly changing pressures, or
separation; make sure y+
values for wall adjacent cells are correct
Options Turn on viscous heating for high Eckert number and turbulent
compressible flows
Materials Use properties database or user defined to create new materials; for
natural convection flows set the density to Boussinesq to use this
approximation or set density to variable (typically use ideal gas for
air); change other properties to variable as well for significant
temperature changes
7. Cell Zone Cond.
Zone Use to set zone as fluid, solid, or porous
Operating Cond. Operating Pressure typically set to atmospheric (101,325 Pa)
Reference Location Only need to set this if there are no pressure boundaries.
Gravity Turn on if natural convection is significant (for Gr/Re2
> 1) and
set Operating Temperature to free stream flow temperature or
coldest boundary temperature for internal flow
Boundary Cond.
Zone Use to define boundary condition and type; for incompressible
flows typically use velocity inlet and pressure outlet; for
compressible flows must use mass-flow inlet and specify mass-
flow rate or mass flux or pressure inlet; for both of these the
specified temperature is the total temperature
Reference Values Set reference values for properties and parameters for calculations
of variables such as drag coefficient or surface Nusselt number
4. Solution
Solution Methods
Press.-Vel. Coup. Select SIMPLE, SIMPLEC (for faster convergence for some
cases), PISO (for unsteady problems), or coupled (for compressible
or natural convection)
Spatial Discret.
Gradient Select Green-Gauss Cell Based (for structured mesh) or Least
Squares Cell Based (for unstructured mesh)
Pressure Select 1st order (faster convergence), 2nd
order (for higher
accuracy), PRESTO! (for transient problems), or Body Force
Weighted (for natural convection or swirling)
Upwinding For Momentum, Energy, and Turbulent equations select 1st
order
(faster convergence), 2nd
order (for higher accuracy), Power-Law,
or QUICK (for higher accuracy on structured grids); use higher
order upwinding to reduce numerical diffusion
Solution Controls
Relaxation Set for each equation; may need to decrease for convergence;
decrease relaxation for energy to 0.7-0.9 for natural convection
and compressible flows
Advanced Use to set multigrid parameters
Monitors
Residuals Set absolute criteria to desired values (10-6
recommended)
Surface Mon. Use to check additional variables (such as total mass flow in and
Volume Mon. out) for convergence or to record results for transient problems
8. Solution Init.
Compute From Can use inlet conditions for initial values (good for k and ε)
Initialize Sets values as initial guess or initial condition for transient
Calc. Activities
Autosave Every Use to save data at any intermediate iteration or time step
Sol. Animations For transient problems set parameters to make animation(s)
File/Write/Case Save a copy of the case before iterating for a solution
Run Calculation
Check Case Use to check model setup
Calculate Enter number of iterations for a steady solution or time step,
number of steps, and maximum number of iterations for transient
File/Write/Case & Data Save a copy of the case and data after converging to a solution
5. Results
Graphics and Animations
Graphics
Contours Use to visualize contour plots of temperature, pressure, velocity,
etc.; use Colormap to change options such as number formatting
for contour plots; use Views to return to original view or to mirror
the solution for cases with symmetry; use New Surface to create a
new point, line, or plane in the flow for plotting
Vectors Use to visualize velocity vectors for solution
Animations
Playback Use to visualize animations for unsteady solutions
Plots
XY Plot Use to make x-y plots such as velocity and temperature profiles at
boundaries; data can be plotted or written to a file; for turbulent
flows verify y+
values at walls are correct for near wall treatment
Reports
Fluxes Use to output mass flow rate or heat transfer rate across boundaries
Forces Use to output forces and drag coefficients for boundaries
6. Report/Input Summary: Use to output a text file(s) summarizing model setup.
7. Define/Custom Field Functions: Use to define new variables such as the Reynolds number
as a function of the x-coordinate location.
8. Adapt/Gradient: Use grid adaptation to refine grid and improve accuracy. Refine grid until
solution is no longer significantly dependent on grid resolution.
9. NOTES ON JUDGING CONVERGENCE:
Residuals are used to monitor the convergence of simulations in FLUENT. For the pressure
based solver recall that the discretized conservation equation for a general variable φ at cell P is
written as
€
aP φP = anb φnb
nb
∑ + b
where aP is the center coefficient, anb are coefficients for the neighboring cells, and b results from
the boundary conditions and source terms. After each iteration the “scaled” residual is calculated
by summing over all cells the imbalance in the discretized conservation equation above and then
normalizing the result using the term shown in the denominator below
€
Rφ
=
anb φnb
nb
∑ + b − aP φP
Ncells
∑
aP φP
Ncells
∑
Residual definitions are often useful for judging convergence for many classes of problems, but
are sometimes misleading. As a result, there are no universal metrics for judging convergence.
Thus, it is a good idea to judge convergence not only by examining residual levels, but also by
monitoring relevant integrated quantities such as mass flux or total heat transfer.
1. If an initial guess for a solution is very good the residual values will not decrease significantly
even though a converged solution has been reached.
2. If the variable of interest is nearly zero everywhere, the residuals may not decrease
significantly. In fully-developed pipe flow, for example, the cross-sectional velocities are zero. If
these velocities have been initialized to zero, initial (and final) residuals are both close to zero.
3. If the governing equation contains non-linear source terms that are zero at the beginning of the
calculation and build up slowly during computation, the residuals may not drop significantly. In
the case of natural convection in an enclosure, for example, initial momentum residuals may be
very close to zero because the initial uniform temperature guess does not generate buoyancy. The
initial nearly-zero residual is not a good scale for the residual.
4. For some equations, such as for turbulence quantities, a poor initial guess may result in high
scale factors. In such cases, scaled residuals will start low, increase as non-linear sources build
up, and eventually decrease. It is therefore good practice to judge convergence not just from the
value of the residual itself, but from its behavior. You should ensure that the residual continues
to decrease (or remain low) for several iterations (approximately 50 or more) before concluding
that the solution has converged.