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XiFoam enthalpy equation in partially premixed case

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Old   May 21, 2015, 11:14
Smile XiFoam enthalpy equation in partially premixed case
  #1
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Guilherme Sempionato
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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.
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Last edited by sempionato; May 21, 2015 at 14:18.
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Old   June 6, 2016, 05:44
Default XiFoam enthalpy equation in partially premixed case
  #2
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Naman Jain
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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.
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Old   March 10, 2020, 02:42
Default I have a same problem..
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Sangmin Kim
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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-
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Old   March 11, 2022, 06:27
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lom
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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
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