OpenFOAM散热器自然散热问题

Do1975

@李东岳这个没有，因为Heatsink的引入是通过代码实现的，所以我是基于官方求解器上进行添加的。大部分都没有动原来官方求解器代码。
另外一个考虑是，官方使用的是湍流模型，而我使用的是层流模型，有点不一样。

李东岳

你有没有用过chtMultiRegionFoam，可以处理多域传热问题

Do1975

@李东岳李老师，这个求解器我还没用过。
目前我是按拓扑优化的处理方式来计算多域传热问题，有点类似《无痛苦N-S方程笔记》中Darcy-Brinkman-Stokes 方程的处理方式。
【在我的模型中，源项为si=-alpha*u，其中alpha由gamma来控制，gamma=1代表Air，gamma=0代表Heatsink】

图1 Darcy-Brinkman-Stokes介绍

图2 自然散热拓扑优化模型[source: Applied Energy 314 (2022) 118984]

李东岳

文章下载不下来。不知道你的导热系数DT是不是有个明确的固体气体分界。

Do1975

好像找到问题了。
我把tolerance从1e-6改为1e-5计算就可以收敛了，到100000步的时候温度不再发生变化。
但是想请教下各位老师，tolerance这种一般如何设置呢？有什么依据来源？还是说只能根据模型来进行调试？

图1 fvSolution设置

Do1975

@李东岳李老师，是明确的。导热系数使用的是Air(0.024)，Heatsink(237)，并且为常值，不随温度进行变化。

李东岳

瞬态算例应该把你的relTol去掉。你加上relTol，那就是满足relTol就跳出了。

Do1975

@李东岳李老师，我跑了下去掉relTol，和没有去掉的相比，跑出来是一样的。

李东岳

把你的log用文本的形式贴一下

Do1975

DILUPBiCGStab:  Solving for Ux, Initial residual = 2.52879e-12, Final residual = 2.52879e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 4.759e-13, Final residual = 4.759e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 1.12742e-08, Final residual = 4.99184e-09, No Iterations 1
time step continuity errors : sum local = 9.26478e-12, global = -1.95551e-19, cumulative = -1.76865e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 4.08769e-12, Final residual = 4.08769e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 7.69458e-13, Final residual = 7.69458e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 3.05161e-09, Final residual = 3.05161e-09, No Iterations 0
time step continuity errors : sum local = 5.66373e-12, global = -3.93401e-18, cumulative = -1.76869e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 3.31261e-12, Final residual = 3.31261e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 6.5252e-13, Final residual = 6.5252e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 3.57218e-09, Final residual = 3.57218e-09, No Iterations 0
time step continuity errors : sum local = 6.6299e-12, global = -3.50639e-18, cumulative = -1.76873e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 2.81837e-12, Final residual = 2.81837e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 5.66173e-13, Final residual = 5.66173e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 5.30704e-09, Final residual = 5.30704e-09, No Iterations 0
time step continuity errors : sum local = 9.84979e-12, global = 8.65936e-19, cumulative = -1.76872e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 2.48061e-12, Final residual = 2.48061e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 5.01799e-13, Final residual = 5.01799e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 7.25581e-09, Final residual = 7.25581e-09, No Iterations 0
time step continuity errors : sum local = 1.34667e-11, global = -7.49204e-18, cumulative = -1.76879e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 2.20698e-12, Final residual = 2.20698e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 4.5362e-13, Final residual = 4.5362e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 8.96308e-09, Final residual = 8.96308e-09, No Iterations 0
time step continuity errors : sum local = 1.66353e-11, global = -2.10879e-18, cumulative = -1.76882e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 1.98591e-12, Final residual = 1.98591e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 4.17482e-13, Final residual = 4.17482e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 1.04578e-08, Final residual = 4.41247e-09, No Iterations 1
time step continuity errors : sum local = 8.18947e-12, global = -6.46356e-18, cumulative = -1.76888e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 4.01256e-12, Final residual = 4.01256e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 7.47198e-13, Final residual = 7.47198e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 2.55585e-09, Final residual = 2.55585e-09, No Iterations 0
time step continuity errors : sum local = 4.74361e-12, global = -9.69952e-19, cumulative = -1.76889e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 3.26589e-12, Final residual = 3.26589e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 6.35781e-13, Final residual = 6.35781e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 3.36828e-09, Final residual = 3.36828e-09, No Iterations 0
time step continuity errors : sum local = 6.25147e-12, global = -2.50355e-18, cumulative = -1.76892e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 2.81174e-12, Final residual = 2.81174e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 5.53575e-13, Final residual = 5.53575e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 5.49292e-09, Final residual = 5.49292e-09, No Iterations 0
time step continuity errors : sum local = 1.01948e-11, global = 1.63108e-18, cumulative = -1.7689e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 2.47921e-12, Final residual = 2.47921e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 4.92095e-13, Final residual = 4.92095e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 7.48208e-09, Final residual = 7.48208e-09, No Iterations 0
time step continuity errors : sum local = 1.38866e-11, global = -2.32211e-18, cumulative = -1.76892e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 2.20866e-12, Final residual = 2.20866e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 4.45864e-13, Final residual = 4.45864e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 9.21963e-09, Final residual = 9.21963e-09, No Iterations 0
time step continuity errors : sum local = 1.71115e-11, global = 1.08066e-18, cumulative = -1.76891e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 1.99261e-12, Final residual = 1.99261e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 4.10956e-13, Final residual = 4.10956e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 1.07404e-08, Final residual = 4.80571e-09, No Iterations 1
time step continuity errors : sum local = 8.91934e-12, global = -3.39057e-18, cumulative = -1.76895e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 4.25332e-12, Final residual = 4.25332e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 7.89251e-13, Final residual = 7.89251e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 2.91529e-09, Final residual = 2.91529e-09, No Iterations 0
time step continuity errors : sum local = 5.41074e-12, global = 8.02024e-19, cumulative = -1.76894e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 3.4724e-12, Final residual = 3.4724e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 6.68648e-13, Final residual = 6.68648e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 3.84833e-09, Final residual = 3.84833e-09, No Iterations 0
time step continuity errors : sum local = 7.14245e-12, global = 4.1512e-19, cumulative = -1.76893e-13
DILUPBiCGStab:  Solving for Ux, Initial residual = 3.01207e-12, Final residual = 3.01207e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 5.79223e-13, Final residual = 5.79223e-13, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 9.9999e-06, Final residual = 9.9999e-06, No Iterations 0
DICPCG:  Solving for p_rgh, Initial residual = 6.1755e-09, Final residual = 6.1755e-09, No Iterations 0
time step continuity errors : sum local = 1.14616e-11, global = -6.35775e-18, cumulative = -1.769e-13
Time = 120000

ExecutionTime = 834.37 s  ClockTime = 834 s

Do1975

算到后面No Iterations都显示的0了

李东岳

瞬态还是稳态求解器？瞬态的话为什么没有时间步信息，稳态的话好像有时间项。没看明白老铁。

Do1975

时间信息没有打印出来，在代码中我注释掉了。

while (simple.loop(runTime))
    {
        // Info<< "Time = " << runTime.timeName() << nl << endl;

        // Pressure-velocity SIMPLE corrector
        {
            #include "UEqn.H"
            #include "TEqn.H"
            #include "pEqn.H"
        }

        laminarTransport.correct();
        turbulence->correct();

        runTime.write();
           
    }
    Info<< "Time = " << runTime.timeName() << nl << endl;

    Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s"
            << "  ClockTime = " << runTime.elapsedClockTime() << " s"
            << nl << endl;

李东岳

你这个在后期已经完全的收敛了不会进行任何计算了。最开始的log贴一下看看

Do1975

@李东岳李老师，这是计算初始的log

/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
Build  : 6-fa1285188035
Exec   : NaturalConvection -parallel
Date   : May 22 2024
Time   : 23:08:20
Host   : "ubuntu"
PID    : 5459
I/O    : uncollated
Case   : /home/hyc2/OpenFOAM_RUN/0_SIMP/NaturalConvection/Parallel_version/Case/app2
nProcs : 28
Slaves : 
27
(
"ubuntu.5460"
"ubuntu.5461"
"ubuntu.5462"
"ubuntu.5463"
"ubuntu.5464"
"ubuntu.5465"
"ubuntu.5466"
"ubuntu.5467"
"ubuntu.5468"
"ubuntu.5469"
"ubuntu.5470"
"ubuntu.5471"
"ubuntu.5472"
"ubuntu.5473"
"ubuntu.5474"
"ubuntu.5475"
"ubuntu.5476"
"ubuntu.5477"
"ubuntu.5478"
"ubuntu.5479"
"ubuntu.5480"
"ubuntu.5481"
"ubuntu.5482"
"ubuntu.5483"
"ubuntu.5484"
"ubuntu.5485"
"ubuntu.5486"
)

Pstream initialized with:
    floatTransfer      : 0
    nProcsSimpleSum    : 0
    commsType          : nonBlocking
    polling iterations : 0
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0


SIMPLE: No convergence criteria found

Reading thermophysical properties

Reading field gamma: Generate Heatsink

Reading field T

Reading field p_rgh

Reading field U

Reading/calculating face flux field phi

Selecting incompressible transport model Newtonian
Creating turbulence model

Selecting turbulence model type laminar
Selecting laminar stress model Stokes
Reading field alphat


Reading g

Reading hRef
Calculating field g.h

No MRF models present

Radiation model not active: radiationProperties not found
Selecting radiationModel none
No finite volume options present

Starting time loop

DILUPBiCGStab:  Solving for Ux, Initial residual = 2.26016e-12, Final residual = 2.26016e-12, No Iterations 0
DILUPBiCGStab:  Solving for Uy, Initial residual = 5.55456e-12, Final residual = 5.55456e-12, No Iterations 0
DILUPBiCGStab:  Solving for T, Initial residual = 1, Final residual = 4.19741e-06, No Iterations 2
DICPCG:  Solving for p_rgh, Initial residual = 0.9978, Final residual = 8.46846e-09, No Iterations 285
time step continuity errors : sum local = 3.21147e-18, global = 3.8703e-28, cumulative = 3.8703e-28
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.259229, Final residual = 2.413e-06, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.247759, Final residual = 1.26753e-06, No Iterations 1
DILUPBiCGStab:  Solving for T, Initial residual = 0.3081, Final residual = 1.17625e-06, No Iterations 2
DICPCG:  Solving for p_rgh, Initial residual = 0.429708, Final residual = 9.40879e-09, No Iterations 282
time step continuity errors : sum local = 7.68457e-15, global = -3.36581e-20, cumulative = -3.36581e-20
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.198942, Final residual = 1.74793e-06, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.138458, Final residual = 1.76607e-06, No Iterations 1
DILUPBiCGStab:  Solving for T, Initial residual = 0.183205, Final residual = 6.90531e-07, No Iterations 2
DICPCG:  Solving for p_rgh, Initial residual = 0.223346, Final residual = 8.62887e-09, No Iterations 281
time step continuity errors : sum local = 7.66024e-15, global = 6.73161e-20, cumulative = 3.36581e-20
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.151191, Final residual = 1.30986e-06, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.0986773, Final residual = 1.98811e-06, No Iterations 1
DILUPBiCGStab:  Solving for T, Initial residual = 0.130488, Final residual = 8.37963e-06, No Iterations 2
DICPCG:  Solving for p_rgh, Initial residual = 0.156401, Final residual = 9.06892e-09, No Iterations 280
time step continuity errors : sum local = 7.64333e-15, global = -3.75832e-28, cumulative = 3.36581e-20
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.120235, Final residual = 1.04164e-06, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.092295, Final residual = 1.95079e-06, No Iterations 1
DILUPBiCGStab:  Solving for T, Initial residual = 0.101424, Final residual = 6.04994e-06, No Iterations 2
DICPCG:  Solving for p_rgh, Initial residual = 0.12596, Final residual = 9.2546e-09, No Iterations 279
time step continuity errors : sum local = 7.5916e-15, global = -3.33951e-20, cumulative = 2.62952e-22
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.0985023, Final residual = 8.79964e-07, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.0805056, Final residual = 1.83179e-06, No Iterations 1
DILUPBiCGStab:  Solving for T, Initial residual = 0.0830071, Final residual = 4.77933e-06, No Iterations 2
DICPCG:  Solving for p_rgh, Initial residual = 0.110625, Final residual = 9.08261e-09, No Iterations 279
time step continuity errors : sum local = 7.66431e-15, global = 6.32595e-28, cumulative = 2.62953e-22
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.0821466, Final residual = 7.69235e-07, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.0689735, Final residual = 1.70448e-06, No Iterations 1
DILUPBiCGStab:  Solving for T, Initial residual = 0.0702824, Final residual = 4.13367e-06, No Iterations 2
DICPCG:  Solving for p_rgh, Initial residual = 0.105393, Final residual = 8.86695e-09, No Iterations 279
time step continuity errors : sum local = 7.71868e-15, global = 3.36581e-20, cumulative = 3.3921e-20
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.0699188, Final residual = 6.85981e-07, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.0600396, Final residual = 1.58394e-06, No Iterations 1
DILUPBiCGStab:  Solving for T, Initial residual = 0.060963, Final residual = 3.73141e-06, No Iterations 2
DICPCG:  Solving for p_rgh, Initial residual = 0.107299, Final residual = 9.0363e-09, No Iterations 278
time step continuity errors : sum local = 7.69957e-15, global = 3.36581e-20, cumulative = 6.75791e-20
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.0607945, Final residual = 6.21142e-07, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.0531695, Final residual = 1.47411e-06, No Iterations 1
DILUPBiCGStab:  Solving for T, Initial residual = 0.0538401, Final residual = 3.43971e-06, No Iterations 2
DICPCG:  Solving for p_rgh, Initial residual = 0.111654, Final residual = 9.04241e-09, No Iterations 278
time step continuity errors : sum local = 7.78919e-15, global = -2.62945e-22, cumulative = 6.73161e-20
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.0537628, Final residual = 5.69473e-07, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.0478181, Final residual = 1.37697e-06, No Iterations 1
DILUPBiCGStab:  Solving for T, Initial residual = 0.0482197, Final residual = 3.21353e-06, No Iterations 2
DICPCG:  Solving for p_rgh, Initial residual = 0.117545, Final residual = 9.42683e-09, No Iterations 277
time step continuity errors : sum local = 7.72011e-15, global = -3.33951e-20, cumulative = 3.3921e-20
DILUPBiCGStab:  Solving for Ux, Initial residual = 0.0483543, Final residual = 5.27961e-07, No Iterations 1
DILUPBiCGStab:  Solving for Uy, Initial residual = 0.0434155, Final residual = 1.29181e-06, No Iterations 1
DILUPBiCGStab:  Solving for T, Initial residual = 0.0436704, Final residual = 3.07378e-06, No Iterations 2
DICPCG:  Solving for p_rgh, Initial residual = 0.124436, Final residual = 9.52381e-09, No Iterations 277
time step continuity errors : sum local = 7.77171e-15, global = -2.62968e-22, cumulative = 3.36581e-20

李东岳

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.259229, Final residual = 2.413e-06, No Iterations 1

你这个看起来并没有读取relTol 0.1的信息。正常应该是这样类似：

DILUPBiCGStab:  Solving for Ux, Initial residual = 0.259229, Final residual = 0.259229/10

咋回事就不知道了，需要详细debug。所有变量都没有读取relTol。不过无所谓。反正是瞬态。

另外，你的瞬态求解器里面，每个方程压力方程只求解一次，这个要最少2次。

Do1975

@李东岳好的，谢谢李老师
我试试在求解器中把压力计算循环两次看看效果。

Do1975

好像没法直接循环两次，我通过下述方式处理计算直接报错了，有其他方式可以保证压力方程求解2次嘛？

for(int i=0;i<2;i++)
{
     #include "pEqn.H"
}

李东岳

压力循环两次不是简单的循环两次，这里面涉及到速度压力耦合求解。类似那种for循环两次压力方程，这是不可以的。你最好找个现有的pimplefoam来植入你的方程。而不是自己写。

Do1975

问题已解决。
经过调试，自己写的求解器没有问题，fvSolution的relaxationFactors需要修改。
原本relaxationFactors设置为：

relaxationFactors
{
    fields
    {
        p_rgh           0.7;
    }
    equations
    {
        U               0.3;
        T               0.5;
        "(k|epsilon|R)" 0.7;
    }
}

将p_rgh改为0.3，U改为0.7，去掉T的放缩因子，修改后如下：

relaxationFactors
{
    fields
    {
        p_rgh           0.3;
    }
    equations
    {
        U               0.7;
        "(k|epsilon|R)" 0.7;
    }
}

计算后结果如下图所示（热流密度修改为1.0，迭代步数200）：

CFD中文网

OpenFOAM散热器自然散热问题