| mecbe2002 |
October 8, 2020 03:56 |
Help needed in codedSource - mass source
I am trying to add mass source using "scalarCodedSource" but the simulation diverges in first iteration itself.
Unit of MFR added here is kg/s
Solver i am using is "rhoPimpleFoam"
I tried with "scalarSemiImplicitSource" method using hard coded MFR value it works fine. But for my application i have to calculate MFR real time so I am using "codedSource".
It can be seen that pressure at the location where "mass Source" is being added goes negative.
Please let me know what is wrong with the code.
- Unit of MFR is correct kg/s ?
- source addition per cell volume? If so then MFR/cell volume has to be added as source?
- filedName "rho" is correct for mass source?
Code:
massSourceEffusionHole
{
type scalarCodedSource;
name sourceTime0;
active true;
scalarCodedSourceCoeffs
{
// Mass source variable
fields (rho);
selectionMode points;
points
(
// Sink location i.e. effusion hole inlet
(0.035 0.0335 0.0)
// Source location i.e. effusion hole exit
(0.0385 0.0365 0.0)
);
codeInclude
#{
#};
codeCorrect
#{
#};
codeAddSup
#{
Pout<<"Mass Source Start"<<endl;
const Time& time = mesh().time();
const volScalarField& rhoJet = mesh_.lookupObject<volScalarField>("rho");
const volVectorField& velJet = mesh_.lookupObject<volVectorField>("U");
const volScalarField& pJet = mesh_.lookupObject<volScalarField>("p");
const scalarField& cellVolume = mesh_.V();
// Adding mass source term
scalarField& massSourceEffusionHole = eqn.source();
// Finding the cell corresponding to sink i.e. effusion hole inlet
label cellLabelSink = mesh_.findCell(points_[0]);
// Finding the cell corresponding to source i.e. effusion hole exit
label cellLabelSource = mesh_.findCell(points_[1]);
// Calculation of total pressure at Sink
scalar totalPJet = pJet[cellLabelSink]+(0.5*rhoJet[cellLabelSink]*pow(mag(velJet[cellLabelSink]),2));
Pout<<"Total Pressure at Sink = "<<totalPJet<<endl;
Pout<<"Pressure Source = "<<pJet[cellLabelSource]<<endl;
// Calculation of MFR at Sink
scalar mfrSink = totalPJet*pow((pJet[cellLabelSource]/totalPJet),0.8571)*1.3212*1e-6*sqrt(((2.0*1.4)/(0.4*287.05*300))*(pow((totalPJet/pJet[cellLabelSource]),0.2857)-1));
Pout<<"MFR Sink = "<<mfrSink<<endl;
massSourceEffusionHole[cellLabelSource] += mfrSink;
Pout<<"MFR Sink = "<<massSourceEffusionHole[cellLabelSource]<<endl;
Pout<<"Mass Source End"<<endl;
#};
codeSetValue
#{
#}
// Dummy entry. Make dependent on above to trigger recompilation code
#{
$codeInclude
$codeCorrect
$codeAddSup
$codeSetValue
#};
}
sourceTime0Coeffs
{
$scalarCodedSourceCoeffs;
}
}
Code:
Time = 1
Using dynamicCode for fvOption:: sourceTime0 at line 72 in "/home/system/Projects/Siragugal/GasTubineCombustor/EffusionHoleModel/singleHoleFlatPlate_EffusionBC/constant/fvOptions.massSourceEffusionHole.scalarCodedSourceCoeffs"
Selecting finite volume options model type sourceTime0
Source: sourceTime0
- selecting cells using points
- selected 2 cell(s) with volume 2.3806788e-10
Mass Source Start
Total Pressure at Sink = 220796.55
Pressure Source = 200000
MFR Sink = 0.00040910048
MFR Sink = 0.00040910048
Mass Source End
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for Ux, Initial residual = 0.0032980687, Final residual = 8.0245382e-07, No Iterations 16
smoothSolver: Solving for Uy, Initial residual = 0.99999999, Final residual = 8.8311766e-07, No Iterations 23
smoothSolver: Solving for Uz, Initial residual = 0.99999999, Final residual = 6.778778e-07, No Iterations 15
smoothSolver: Solving for e, Initial residual = 4.2580813e-05, Final residual = 3.1907154e-07, No Iterations 1
Mass Source Start
Total Pressure at Sink = 220796.55
Pressure Source = 200000
MFR Sink = 0.00040910048
MFR Sink = 0.00040910048
Mass Source End
GAMG: Solving for p, Initial residual = 0.00022212445, Final residual = 1.8957863e-05, No Iterations 17
GAMG: Solving for p, Initial residual = 0.00029171794, Final residual = 2.5683858e-05, No Iterations 2
Mass Source Start
Total Pressure at Sink = 220796.54
Pressure Source = 61287.67
MFR Sink = 0.0005830456
MFR Sink = 0.0005830456
Mass Source End
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 1.0513006e-05, global = -7.3666193e-06, cumulative = -7.3666193e-06
Mass Source Start
Total Pressure at Sink = 220796.56
Pressure Source = 61287.67
MFR Sink = 0.00058304562
MFR Sink = 0.00058304562
Mass Source End
GAMG: Solving for p, Initial residual = 0.00027760611, Final residual = 2.3000663e-05, No Iterations 11
GAMG: Solving for p, Initial residual = 0.00017927573, Final residual = 9.6137966e-07, No Iterations 31
Mass Source Start
Total Pressure at Sink = 220796.57
Pressure Source = -50175.002
#0 Foam::error::printStack(Foam::Ostream&) at ??:?
#1 Foam::sigFpe::sigHandler(int) at ??:?
#2 ? in "/lib/x86_64-linux-gnu/libc.so.6"
#3 ? in "/lib/x86_64-linux-gnu/libm.so.6"
#4 pow in "/lib/x86_64-linux-gnu/libm.so.6"
#5 Foam::fv::sourceTime0FvOptionscalarSource::addSup(Foam::fvMatrix<double>&, int) at constant/fvOptions.massSourceEffusionHole.scalarCodedSourceCoeffs:114
#6 ? in "/home/system/OpenFOAM/OpenFOAM-6/platforms/linux64GccDPInt32Opt/bin/rhoPimpleFoam"
#7 ? in "/home/system/OpenFOAM/OpenFOAM-6/platforms/linux64GccDPInt32Opt/bin/rhoPimpleFoam"
#8 ? in "/home/system/OpenFOAM/OpenFOAM-6/platforms/linux64GccDPInt32Opt/bin/rhoPimpleFoam"
#9 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#10 ? in "/home/system/OpenFOAM/OpenFOAM-6/platforms/linux64GccDPInt32Opt/bin/rhoPimpleFoam"
Floating point exception (core dumped)
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