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Problem with coded source term for multiphaseEulerFoam |
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July 7, 2022, 21:23 |
Problem with coded source term for multiphaseEulerFoam
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#1 |
New Member
Shuji Chang
Join Date: Apr 2022
Posts: 4
Rep Power: 4 |
Hi Foamers,
I would like to inquire about the coded source term in OpenFoam. Actually, I'm facing a problem. When I use "codedSourceTerm" in OpenFoam, there are 3 options "codeAddSup", "codeAddRhoSup", and "codeAddAlphaRhoSup". I am not sure what's the meaning of these options. When I went to check the source code in OpenFoam9(https://cpp.openfoam.org/v9/massSource_8H_source.html), I found the description as below: Code:
// Sources //- Add a source term to an equation FOR_ALL_FIELD_TYPES(DEFINE_FV_MODEL_ADD_SUP); //- Add a source term to a compressible equation FOR_ALL_FIELD_TYPES(DEFINE_FV_MODEL_ADD_RHO_SUP); //- Add a source term to a phase equation FOR_ALL_FIELD_TYPES(DEFINE_FV_MODEL_ADD_ALPHA_RHO_SUP); Meanwhile, I am trying to implement the kinetic model into CFD by source term. I used multiphaseEulerFoam as my solver, liquid and gas phase both are multicomponent. Please find my code for the source term below: Code:
Growth { type coded; selectionMode all; field biomass.liquid; codeInclude #{ #include "fvm.H" #}; codeAddRhoSup #{ Pout<< "**codeAddRhoSup**" << endl; const vectorField& C = mesh().C(); // Get the required fields const volScalarField& B = mesh().lookupObject<volScalarField>("biomass.liquid");// mass fraction of biomass const volScalarField& O = mesh().lookupObject<volScalarField>("O2.liquid");// mass fraction of Oxygen const volScalarField& S = mesh().lookupObject<volScalarField>("substrate.liquid");// mass fraction of substrate const volScalarField& rhoL = mesh().lookupObject<volScalarField>("thermo:rho.liquid");// rho of liquid phase // Define the Kinetic parameters //dimensionedScalar mum("mum", dimensionSet(0,0,-1,0,0,0,0), 2.78e-4); // 1/second //dimensionedScalar ks("ks", dimensionSet(1,-3,0,0,0,0,0), 0.05); // kg/m^3 //dimensionedScalar ko("ks", dimensionSet(1,-3,0,0,0,0,0), 1e-4); //kg/m^3 const scalar mum = 2.78e-1; // 2.78e-4 const scalar ks = 0; // 0.05 const scalar ko = 0; // 1e-4 // Get the timestep const scalar deltaT = mesh().time().deltaT().value(); // Creat the growth rate (mu) volScalarField GrowthRate ( IOobject ( "GrowthRate", mesh().time().timeName(), mesh(), IOobject::NO_READ, IOobject::AUTO_WRITE ), mesh(), dimensionedScalar("GrowthRate", dimless/dimTime, 0.0) ); // Compute the growth rate forAll(C, i) { GrowthRate[i] = mum*rhoL[i]; } // Add to source term eqn += GrowthRate*B; #}; When I use codeAddRhoSup, it works. However, when I use it in codeAddAlphaRhoSup, error is reported: Could you please teach me why this error happened? I appreciate your help. Shuji |
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July 14, 2022, 02:40 |
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#2 |
New Member
Almanzo Arjuna
Join Date: Feb 2022
Location: East Java, Indonesia
Posts: 8
Rep Power: 4 |
Hi as a fellow coded source user, with how tiny the documentation on coded source is, I'm not really an expert in this case but I can refer you to this post
coded energysource in fvModels I don't know if this will help you, but as far as I understand codeAddRhoSup is for the compressible solver (e.g. chtMultiRegionFoam) and codeAddSup is for the incompressible one. best of luck. |
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July 22, 2022, 01:37 |
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#3 | ||
New Member
John Parra
Join Date: Jun 2020
Posts: 3
Rep Power: 6 |
Quote:
1) in OF9, now you have to be mindful of the kind of problem you're solving. * for incompressible flows (density doesn't change i.e: flow of liquids in pipes with heat transfer) you probably use "codeAddSup" * for compressible flows (density changes, i.e: gas reaction) you probably use "codeAddRhoSup" in this case, fvModels adds the density to the source term. You can see this in fvModels.C * for multiphase flows, you probably use "codeAddAlphaRhoSup" and fvModels will add the density and alpha required on the source term. 2) When you said Quote:
3) Now, about this error: the source term has units kg/m3 s. Your "GrowthRate" variable has units of 1/s. This is what the code is complaining about. You might think that because you multiplied by a density it fixes the problems, but apparently "volScalarField" are unitless quantities, so your rhoL doesn't have any units; and OF9 complains about LHS being kg/m3s and the RHS being 1/s. I think the following works: Code:
Growth { type coded; selectionMode all; field biomass.liquid; codeInclude #{ #include "fvm.H" #}; codeAddAlphaRhoSup #{ Pout<< "**codeAddAlphaRhoSup**" << endl; const vectorField& C = mesh().C(); // Get the required fields const volScalarField& B = mesh().lookupObject<volScalarField>("biomass.liquid");// mass fraction of biomass const volScalarField& O = mesh().lookupObject<volScalarField>("O2.liquid");// mass fraction of Oxygen const volScalarField& S = mesh().lookupObject<volScalarField>("substrate.liquid");// mass fraction of substrate const volScalarField& rhoL = mesh().lookupObject<volScalarField>("thermo:rho.liquid");// rho of liquid phase // Define the Kinetic parameters dimensionedScalar K_O2("K_O2", dimensionSet(1,-3,0,0,0,0,0), 1.0e-4); //kg/m3 dimensionedScalar ub_max("ub_max", dimensionSet(0,0,-1,0,0,0,0), 0.278); //1/s dimensionedScalar rhoB("rhoB", dimensionSet(1,-3,0,0,0,0,0), 1); //kg/m3 //const scalar mum = 2.78e-1; // 2.78e-4 //const scalar ks = 0; // 0.05 //const scalar ko = 0; // 1e-4 // Get the timestep const scalar deltaT = mesh().time().deltaT().value(); // Creat the growth rate (mu) volScalarField GrowthRate ( IOobject ( "GrowthRate", mesh().time().timeName(), mesh(), IOobject::NO_READ, IOobject::AUTO_WRITE ), mesh(), dimensionedScalar("GrowthRate", dimless/dimTime, 0.0) ); // Compute the growth rate GrowthRate = ub_max*(O/(O + K_CO2/rho)); // Add to source term eqn += GrowthRate*B*rhoX; #}; 1) inside the block "codeAddAlphaRhoSup" you can call "rho" and "alpha" and you'll get the density and the volume fraction of the field. 2) for the growth rate I used the Monod model and divided numerator and denominator by the density, leaving it only in terms of the mass fraction of oxygen. GrowthRate has now units of 1/s 3) rhoX is there just to add the missing units. Th RHS of eqn should have units kg/m3s as well. |
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coded source, multi component, multiphase model, multiphaseeulerfaom, source term |
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