[malydilnar]

Hey all, ive been stuck at this problem for a while and am looking for your insight. I have a multi region conjugate heat transfer problem where I have a heater generating heat in its own region (Through scalar coded source / semi implicit source). I want to be able to turn the heater on/off based on the temperature read in a cell in a different region. (Thermostat controlling the heater)

The problem is it seems like I can only access the mesh inside the region the fvoptions file lives in for the coded source (The heater). Therefore I cant pull the temperature of a specific cell in a different region to use for my thermostat control.

This is my coded source so far, its really just copied parts from other forum users so far. The thermostat if conditions aren't there yet, because I need to figure out how to get the conditional thermostat into the coded source first.

test
{
    type          scalarCodedSource;

    active          true;

    name    sourceTime;



    scalarCodedSourceCoeffs
    {
         selectionMode   all;
         
	       fields      (h);

        codeInclude
        #{

        #};

        codeCorrect
        #{
            Pout<< "**codeCorrect**" << endl;
        #};

        codeAddSup
        #{
	          scalar Tvol = 0;
            //const Time& time = mesh().time();
            const volScalarField& Tm = mesh_.lookupObject<volScalarField>("T"); // Look up temperature
            //Tvol = Tm.weightedAverage(mesh_.V()).value();                //averageValue of the volScalarField
            //const fvMesh& help = Tm.mesh().time();
            const vectorField& C = mesh_.C();                    //List of cellcentres
	          const scalarField& V = mesh_.V();
            //const scalarField& num = mesh_.C().size();
            scalarField& hSource = eqn.source();                //defining source
            forAll(C, i)
            {
                //hSource[i] = (Tvol - 310)*2400*V[i] ;
                hSource[i] = (Tm[2] - 310)*2400*V[i] ;
            }

            // Calling the mesh.C().size() method therefore yields the total size of the mesh.
            Pout << V << endl;
            Pout << "***codeAddSup***" << endl;
        #};

        codeSetValue
        #{
            Pout<< "**codeSetValue**" << endl;
        #};

        // Dummy entry. Make dependent on above to trigger recompilation
        code
        #{
            $codeInclude
            $codeCorrect
            $codeAddSup
            $codeSetValue
        #};
    }

    sourceTimeCoeffs
    {
         $scalarCodedSourceCoeffs;
    }
}

As far as I can tell, mesh_.() only has access to the values of the mesh inside the region, not the combined mesh.

I have a couple of ideas on how to fix my problem, though I'm not very familiar with c++ so its difficult to really read all the source code and understand what methods I have at my disposal.

• figure out how to extend mesh_.() to be able to pull temperature from a different region

• it looks like coded source includes the sampling library, which should allow me to probe values, though again not sure if I can specify a different region to probe

Any input on how to solve my problem would be very appreciated, thanks.

[mecbe2002]

hi,


My problem is also similar to your..


I want to apply MFR at source point. To calculate MFR, pressure drop calculation has to be used, for this i need to get pressure at different locations and calculate MFR and then apply MFR at one of the location.


in fvOptions i can specify only one point where MFR has to be specified.



Did you able to found a way to do this?

[olesen]

From mesh_ you can access the time database, from there you have access to the various mesh regions.

[mecbe2002]

Objective of my work is to replace small diameter pipe (dia <0.5 mm) with source and sink terms i.e. inlet of the pipe will be sink and outlet of the pipe is source.
I have to use pressure drop across the pipe to calculate the mass flow rate; for this i need to get pressure at inlet and exit of the pipe.

• selection mode - points
• i have specified inlet and exit of the pipe location

In the below code, inside the "forAll" loop i can access only pressure values of current point in the loop. But i need to get pressure value at some other point for MFR calculation. How to do this?

 codeAddSup
#{            
     const volScalarField& rhoJet = mesh_.lookupObject<volScalarField>("rho");
     const volVectorField& velJet = mesh_.lookupObject<volVectorField>("v1");
     scalarField& massSource1 = eqn.source();
     const labelList& cellIDs = cells();
            
      forAll(cellIDs, i)
      {
          label cellSource = cellIDs[i];
           
          massSource1[cellSource] += rhoJet[cellSink]*mag(velJet[cellSink])*6.28319*1e-6;               
      }                          
#};

[lmw354]

Did you guys find a solution.