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constantEmissivity option in view factor radiation model |
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June 27, 2022, 13:30 |
constantEmissivity option in view factor radiation model
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Hi Foamers,
Usually I set the option "constantEmissivity" in the view factor radiation model to true because I used the lookup model with constant emissivity in the past. Recently I implemented a submodel for boundaryProperties such that the emissivity changes over time so I started to look more into this option. Apparently the emissivity still changes over time when setting constantEmissivity to true. This is because the function to update the emissivity is called regardless of the option: In radiation::viewFactor::calculate() Code:
const tmp<scalarField> teb = boundaryRadiation.emissivity(patchID, bandI); Also in radiation::viewFactor::calculate() Code:
if (!constEmissivity_) { scalarSquareMatrix C(totalNCoarseFaces_, 0.0); for (label i=0; i<totalNCoarseFaces_; i++) { for (label j=0; j<totalNCoarseFaces_; j++) { const scalar invEj = 1.0/E[j]; const scalar sigmaT4 = physicoChemical::sigma.value()*T4[j]; if (i==j) { C(i, j) = invEj - (invEj - 1.0)*Fmatrix_()(i, j); q[i] += (Fmatrix_()(i, j) - 1.0)*sigmaT4 + qrExt[j]; } else { C(i, j) = (1.0 - invEj)*Fmatrix_()(i, j); q[i] += Fmatrix_()(i, j)*sigmaT4; } } } Info<< "Solving view factor equations for band :" << bandI << endl; // Negative coming into the fluid LUsolve(C, q); } else //Constant emissivity { // Initial iter calculates CLU and caches it if (iterCounter_ == 0) { for (label i=0; i<totalNCoarseFaces_; i++) { for (label j=0; j<totalNCoarseFaces_; j++) { const scalar invEj = 1.0/E[j]; if (i==j) { CLU_()(i, j) = invEj-(invEj-1.0)*Fmatrix_()(i, j); } else { CLU_()(i, j) = (1.0 - invEj)*Fmatrix_()(i, j); } } } DebugInFunction << "\nDecomposing C matrix..." << endl; LUDecompose(CLU_(), pivotIndices_); } for (label i=0; i<totalNCoarseFaces_; i++) { for (label j=0; j<totalNCoarseFaces_; j++) { const scalar sigmaT4 = constant::physicoChemical::sigma.value()*T4[j]; if (i==j) { q[i] += (Fmatrix_()(i, j) - 1.0)*sigmaT4 + qrExt[j]; } else { q[i] += Fmatrix_()(i, j)*sigmaT4; } } } Info<< "Solving view factor equations for band : " << bandI << endl; LUBacksubstitute(CLU_(), pivotIndices_, q); iterCounter_ ++; } Does anyone know more about this? Thanks in advance! |
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emissivity, radiation model, view factor model |
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