# XiFoam enthalpy equation in partially premixed case

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 May 21, 2015, 11:14 XiFoam enthalpy equation in partially premixed case #1 New Member   Guilherme Sempionato Join Date: Aug 2011 Posts: 12 Rep Power: 14 Hi all, I am researching now the possible XiFoam implementation to a partially pre-mixed combustion case but there are some terms in enthalpy equation that are puzzling me. There is a annotated possible solution in EauEqn.H but I could not encounter a specific paper to detail this solution to a secure implementation. if (ign.ignited()) { volScalarField& heau = thermo.heu(); fvScalarMatrix heauEqn ( fvm::ddt(rho, heau) + mvConvection->fvmDiv(phi, heau) + (fvc::ddt(rho, K) + fvc::div(phi, K))*rho/thermo.rhou() + ( heau.name() == "eau" ? fvc::div ( fvc::absolute(phi/fvc::interpolate(rho), U), p, "div(phiv,p)" )*rho/thermo.rhou() : -dpdt*rho/thermo.rhou() ) - fvm::laplacian(turbulence->alphaEff(), heau) // These terms cannot be used in partially-premixed combustion due to // the resultant inconsistency between ft and heau transport. // A possible solution would be to solve for ftu as well as ft. //- fvm::div(muEff*fvc::grad(b)/(b + 0.001), heau) //+ fvm::Sp(fvc::div(muEff*fvc::grad(b)/(b + 0.001)), heau) == fvOptions(rho, heau) ); fvOptions.constrain(heauEqn); heauEqn.solve(); fvOptions.correct(heau); } The temperature field is presenting some discrepancies in partially premixed cases and I think that is due this terms. Does someone knows more about this commented possible solution? Thanks, Guilherme Sempionato. dmytro.iurashev likes this. Last edited by sempionato; May 21, 2015 at 14:18.

 June 6, 2016, 05:44 XiFoam enthalpy equation in partially premixed case #2 New Member   Naman Jain Join Date: Sep 2015 Location: India Posts: 4 Rep Power: 10 Hi Sempionato, I am working on XiFoam to analyze the combustion of a lean premixed mixture and saw those lines in the EaEqn.H file. Have you found anything related to it? Eagerly waiting for your reply, Thanks, Naman.

 March 10, 2020, 02:42 I have a same problem.. #3 New Member   Sangmin Kim Join Date: Aug 2019 Posts: 6 Rep Power: 6 Who can solve this ???? ------------------------------------------------------------------ A possible solution would be to solve for ftu as well as ft. - fvm::div(muEff*fvc::grad(b)/(b + 0.001), heau) + fvm::Sp(fvc::div(muEff*fvc::grad(b)/(b + 0.001)), heau) -------------------------------------------------------------------- <- How to use these terms???? Thanks. -SM-

 March 11, 2022, 06:27 #4 New Member   Join Date: Jul 2019 Posts: 1 Rep Power: 0 Urgent!!! pls volScalarField Db("Db", turbulence->muEff()); These terms cannot be used in partially-premixed combustion due to - fvm::div((Db*fvc::grad(b))/(b + 0.001)), heau) //+ fvm::Sp(fvc::div((Db*fvc::grad(b)/(b + 0.001))), heau) Did any solve this? I tried to create surfacefield for fvm:iv() still not working? Are these terms essential for Partially premix case Thanks lom