[ghorob]

Hi

I want to model a simple transient heat conduction in a solid object with source term. I used laplacianfoam, but I found that it solves in steady state condition.
I put a heat flux on one end of the objects and other sides remained isolated (dT/dx=0). after a while I saw that there is no change in the thermal distribution inside the object .

I tried to add while (runtime.loop()) {} instead of the while (simple.loop()) {} but it still doesn't work.
I was wondering if you help me in this issue:

int main(int argc, char *argv[])
{
    #include "setRootCase.H"
    #include "createTime.H"
    #include "createMesh.H"
    #include "createFields.H"
    simpleControl simple(mesh);

    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

    Info<< "\nCalculating temperature distribution\n" << endl;

    while (runTime.loop())
    
       {
      
        Info<< "Time = " << runTime.timeName() << nl << endl;     
        
        while (simple.correctNonOrthogonal())         
        {
            solve
            (
                fvm::ddt(cp,T) 
        
        - fvm::laplacian(lambda/rho, T)
        
        -(latent)*fvc::ddt(gS)    
    
            );
        }  
        #include "calcgS.H" 
        #include "write.H"

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

    return 0;
}

[ghorob]

Hi

I simulated heat transfer in a cylinder in Cartesian coordinate in OpenFoam using LaplacianFoam.

The initial temperature of the cylinder is 1500c, top and bottom of the cylinder set zeroGrarient (dT/dx=0) and cylinder sides has dT/dx = -2000. Total simulation run is 20000sec.

The purpose is to model a simple transient heat transfer. In this type of problem I expected to see the temperature decrease in every time steps.


My problem is that after around 4000sec the temperature distribution in the cylinder doesn’t change, but openFoam continue running without any error.this problem happen even when I set a fixed boundary condition on the cylinder sides like Tside=1000c.

when I simulated heat transfer in a cube which right face has a flux but other faces are dT/dx=0 the simulation run well and temperature decreases until the end of simulation.

I don't know why this happen when I use cylinder.
I attached solver that I edited (testlaplacian) with 0-constant-system folders.

[ghorob]

Originally Posted by ghorob

Hi

I simulated heat transfer in a cylinder in Cartesian coordinate in OpenFoam using LaplacianFoam.

The initial temperature of the cylinder is 1500c, top and bottom of the cylinder set zeroGrarient (dT/dx=0) and cylinder sides has dT/dx = -2000. Total simulation run is 20000sec.

The purpose is to model a simple transient heat transfer. In this type of problem I expected to see the temperature decrease in every time steps.


My problem is that after around 4000sec the temperature distribution in the cylinder doesn’t change, but openFoam continue running without any error.this problem happen even when I set a fixed boundary condition on the cylinder sides like Tside=1000c.

when I simulated heat transfer in a cube which right face has a flux but other faces are dT/dx=0 the simulation run well and temperature decreases until the end of simulation.

I don't know why this happen when I use cylinder.
I attached solver that I edited (testlaplacian) with 0-constant-system folders.

I add heat to the icoFoam and my problem solved with that solver unsteady and correctly. I think there is something wrong with laplacianFoam in transient problems.