[mecbe2002]

Hi all,


I am trying to implement local source based model to replace "effusion hole" in combustor liners with source and sink model. (details in the attached image)


I want to know how to get pressure value at a certain grid points to calculate the pressure drop across the hole and then calculate the discharge coefficient, to apply mass flow rate at hole center

[geth03]

you can define a little box at the area where you want to measure your pressure with topoSetDict. you need to create a cellZone. you can then access the cells and calculate a pressure average, i don't think that you will be able to create a box as little as a cell. so small enough with averaged pressure should be feasible.

[mecbe2002]

massSourceEffusionHole
{
    type    scalarCodedSource;
    name    sourceTime;
    active  true;
    
    scalarCodedSourceCoeffs
    {            
        
        fields          (rho); 
        selectionMode   points;
        points //sink location
        (
            (0.035 0.034 0.0)
        );  
        codeInclude
        #{
        
        #};
        
        codeCorrect
        #{
        #};
        
        codeAddSup
        #{
            const Time& time1 = mesh().time();
            const volScalarField& rhoJet = mesh_.lookupObject<volScalarField>("rho");
            const volVectorField& velJet = mesh_.lookupObject<volVectorField>("U");
            scalarField& massSource1 = eqn.source();
            const labelList& cellIDs = cells();
        
            forAll(cellIDs, i)
            {
                label cellI = cellIDs[i];                
                massSource1[cellI] = rhoJet[cellI]*mag(velJet[cellI])*6.28319*1e-6;  
            }             
        #};
        
        codeSetValue
        #{
        #}
        
        // Dummy entry. Make dependent on above to trigger recompilation code
        #{
            $codeInclude
            $codeCorrect
            $codeAddSup
            $codeSetValue
        #};
    }
    
    sourceTimeCoeffs
    {
        $scalarCodedSourceCoeffs;    
    }
}

In the selection mode I have used "points" and specified the sink location, then calculating the MFR by getting the "rho" and "vel" at that location. I have applied the same in the sink location.

I need help in applying the MFR calculated at "sink" location to "source" location i.e. (0.0385 0.0365 0.0)


FYI
sink location (0.035 0.034 0.0)
source location (0.0385 0.0365 0.0)


Thanks
KGN