13.1 Heat conduction with source termKnown: Steady heat conduction occurs in fuel-rodwith source.The components and domain size areshown in Fig. 1. The boundary conditions are as follows:Topand bottom boundary--adiabaticCylindrical boundary- convective heat transferFuel-rod-- a constant heat source term6/58
13.1 Heat conduction with source term Known：Steady heat conduction occurs in fuel-rod with source. The components and domain size are shown in Fig. 1. The boundary conditions are as follows: ◼ Fuel-rod- a constant heat source term ◼ Top and bottom boundary- adiabatic ◼ Cylindrical boundary– convective heat transfer 6/58
Adiabatich=3500W/(m2·K)D=14 mmT=150CL=100 mmD=26 mmSourcetermAluminum15000000W/m3Fig.1 Computational domain7/58
Fig.1 Computational domain D=14 mm L=100 mm Source term 15000000W/m3 D=26 mm Aluminum h=3500W/（m2·K) Tf=150℃ Adiabatic 7/58
Find: Temperature distribution in the domain.Solution:div(agradp)+ St = 0It is a heat conduction problem with given GAMA and source term.GAMA and source term are different for different layers.Remark: Constructing the reasonable physical modeland writing down the corresponding governing equation,BC and IC is the first and most important step beforeusingFluent.Fluent is just a tool for solving above problem !Background of NHThelps youto use thetoolbetter8/58
Solution: * div grad S ( ) 0 + = It is a heat conduction problem with given GAMA and source term. GAMA and source term are different for different layers. Find: Temperature distribution in the domain. Remark: Constructing the reasonable physical model and writing down the corresponding governing equation, BC and IC is the first and most important step before using Fluent. Fluent is just a tool for solving above problem ! Background of NHT helps you to use the tool better. 8/58
StarttheFluentsoftwareDinensionO2DO3D1.Choose3-DimensionOptionsDoublePrecision2. Choose display optionsDisplayMeshAfterReadingDLoad ACI3.ChooseParallelprocessingOStart ServerParallel (Local Iachineoption204Solver ProcessesASolver GPGPUs per achine0Note:Double precision or SingleprecisionFor most cases the single precision version of Fluent is sufficient.Nevertheless, for heat transfer problem,ifthethermalconductivity ratio between different components are high, it isrecommendedtouseDoublePrecisionVersion9/58
Start the Fluent software 1. Choose 3-Dimension 2. Choose display options 3. Choose Parallel processing option Note: Double precision or Single precision For most cases the single precision version of Fluent is sufficient. Nevertheless, for heat transfer problem, if the thermal conductivity ratio between different components are high, it is recommended to use Double Precision Version. 9/58
Stepl:Readand checkthemeshThe mesh is generated by pre-processing software such asMESHING,ICEM andGAMBIT.The document is with suffix".msh"（后缀名）This step is similarto theGrid subroutine(UGRID,Setup1) inourgeneralteachingcode.MeshReadDomainFilePhysicsReadMesh....Write1Case...Data...ImportCase&DataExportExportto CFD-Post..PDF...10/58
Step 1: Read and check the mesh ◼ The mesh is generated by pre-processing software such as MESHING，ICEM and GAMBIT. The document is with suffix (后缀名）“.msh” ◼ This step is similar to the Grid subroutine (UGRID, Setup1) in our general teaching code. Mesh→Read 10/58