Fluid Dynamics: k-e Turbulence Model
24 Questions
0 Views

Fluid Dynamics: k-e Turbulence Model

Created by
@JudiciousChrysoprase4661

Questions and Answers

What is the purpose of using the k–e turbulence model in this study?

  • To simplify the flow analysis
  • To analyze compressible flow
  • To model turbulent flow in the channel (correct)
  • To derive the energy equation
  • The Reynolds average Navier–Stokes equations are used for numerical analysis in this study.

    True

    What does a continuity equation in fluid dynamics represent?

    It represents the conservation of mass in a fluid flow.

    The transient solution of the computational fluid dynamics model involves _____ generated by the battery during discharge.

    <p>variable heat</p> Signup and view all the answers

    What convergence criteria is set for the numerical analysis in this study?

    <p>1 × 10−6</p> Signup and view all the answers

    What software was used for the computational fluid dynamics modeling?

    <p>ANSYS FLUENT</p> Signup and view all the answers

    In the standard k–e turbulence model, __ and __ are constants in the turbulent kinetic energy equation.

    <p>C, μ</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Continuity Equation = Conservation of mass in a fluid flow Navier–Stokes Equation = Governing equations for fluid motion RANS = Time-averaged equations for turbulent flow Turbulent Flow = Irregular, chaotic fluid motion</p> Signup and view all the answers

    What is primarily responsible for turbulent kinetic energy caused by mean velocity gradient?

    <p>Gk</p> Signup and view all the answers

    The turbulent kinetic energy caused by buoyancy is represented by Gb.

    <p>True</p> Signup and view all the answers

    What is the equation used to calculate turbulence viscosity (μt)?

    <p>μt = k * ε * Cμ</p> Signup and view all the answers

    The constants C1ε, C2ε, and C3ε are used as model ______ in the equations.

    <p>constants</p> Signup and view all the answers

    What term in the equation represents the contribution of undulating expansion in compressible turbulence to overall dispersion velocity?

    <p>Ym</p> Signup and view all the answers

    Thermal radiation is significant at the operating temperature of the battery.

    <p>False</p> Signup and view all the answers

    What is the main method of heat transfer from the battery pack to the cooling plate?

    <p>Heat conduction</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>σk = Turbulent Prandtl number of k Sk = User-defined resource item Cμ = Coefficient related to turbulence viscosity Sε = User-defined resource for ε</p> Signup and view all the answers

    What is the inlet flow velocity set for the flow channel?

    <p>0.1 m/s</p> Signup and view all the answers

    The outlet condition of the flow channel is set to a gauge pressure of 101325 Pa.

    <p>False</p> Signup and view all the answers

    What is the assumed initial temperature for the computational domains in the simulations?

    <p>298.15 K</p> Signup and view all the answers

    The transfer equation used in ANSYS FLUENT for thermal analysis is based on the __________ model.

    <p>standard k-e</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>ρ = Density (kg/m3) μ = Viscosity (Pa·s) V = Flow velocity (m/s) P = Pressure (Pa)</p> Signup and view all the answers

    What method is used for velocity pressure coupling in the analysis?

    <p>Semi-implicit method</p> Signup and view all the answers

    The turbulent viscosity is represented as μt in the governing equations.

    <p>True</p> Signup and view all the answers

    What is the Reynolds stress gradient represented by in the governing equations?

    <p>λ</p> Signup and view all the answers

    Study Notes

    Turbulence Modeling and Analysis

    • Utilizes standard k–e turbulence model, specifically designed for turbulent fluid flow due to vortex generator.
    • Incorporates enhanced wall treatment, emphasizing the complexity of analytical turbulence solutions.
    • Turbulence viscosity (μt) is defined as μt = Cμρ/ε, where C and μ are constants.

    Computational Fluid Dynamics (CFD) Model

    • ANSYS FLUENT chosen for its flexibility in modeling complex fluid dynamics.
    • Numerical analysis involves continuity and Navier–Stokes equations, moving towards a steady-state solution.
    • Convergence criteria established with residuals reduced to 1 × 10^−6 for continuity, momentum, and energy equations.

    Boundary Conditions and Thermal Analysis

    • Model operates under transient conditions due to variable heat generation from battery discharge.
    • Heat is transferred from the battery to the cooling plate, followed by absorption into the coolant.
    • Inlet flow velocity is set to 0.1 m/s with outlet maintained at gauge pressure of 0 Pa.
    • Initial and ambient temperatures assumed at 298.15 K for all simulations.

    Grid Independence and Model Setup

    • 3D modeling of the liquid cooling system (BTMS) conducted using SPACECLAIM with mesh module for grid division.
    • Fluent employed for calculating the 3D heat flow coupling model due to the complexity of the channel shape.
    • The semi-implicit method of pressure connection equation is utilized for velocity-pressure coupling.

    Heat Generation Rate

    • Battery heat generation rates assessed under various charging scenarios, indicating performance variability and importance of thermal management in battery systems.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    This quiz explores the standard k-e turbulence model and its application in fluid dynamics, particularly focusing on turbulent flow in the presence of a vortex generator. Understand key concepts such as turbulent viscosity and enhanced wall treatment. Test your knowledge of the underlying principles that govern turbulent flow in channels.

    More Quizzes Like This

    Clear Air Turbulence Quiz
    3 questions

    Clear Air Turbulence Quiz

    IrreproachableChalcedony3316 avatar
    IrreproachableChalcedony3316
    Final Closure Models for Turbulence
    5 questions

    Final Closure Models for Turbulence

    CompliantLeaningTowerOfPisa avatar
    CompliantLeaningTowerOfPisa
    Wake Turbulence Safety Guidelines
    6 questions
    Use Quizgecko on...
    Browser
    Browser