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May 26, 2016, 07:21 |
How is the thermal conductivity calculated?
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#1 |
Member
Pedro
Join Date: Nov 2014
Posts: 50
Rep Power: 11 |
Hello Foamers
I'm trying to figure out how does openFoam calculate the thermal diffusivity in BuyoantSimpleFoam. So far all the answers I've found online only go as deep as saying that alpha = nu / prandtl, but how is Prandtl calculated? In other words, how does OpenFoam goes from a Pressure Field, Temperature Field and the properties listed below to alphaEff? Code:
thermoType { type heRhoThermo; mixture pureMixture; transport sutherland; thermo hConst; equationOfState perfectGas; specie specie; energy sensibleEnthalpy; } pRef 101325; mixture { specie { nMoles 1; molWeight 28.96; } thermodynamics { Cp 1006; Hf 0; } transport { As 1.458e-06; Ts 110.555; } } |
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May 27, 2016, 10:05 |
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#2 |
Senior Member
Mahdi Hosseinali
Join Date: Apr 2009
Location: NB, Canada
Posts: 273
Rep Power: 18 |
Looking at EEqn you'll see turbulence->alphaEff, then searching for turbulence you'll figure out it's been defined in createFields.H by autoPtr<compressible::turbulenceModel> turbulence, so you gotta look into documents to find Foam::compressible::turbulenceModel. However as thermo is mentioned in the turbulence model you can guess right here it's coming from thermo. It's again defined at createFields.H.
(following turbulence model gets you to phase fraction alpha which I doubt is what you want). checking rhoThermo which is defined at very first lines of createField.H you find this: http://openfoam.com/documentation/cp...ml/a02284.html there you can follow up the alphaEff definition. |
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May 29, 2016, 14:33 |
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#3 |
Member
Pedro
Join Date: Nov 2014
Posts: 50
Rep Power: 11 |
Thank you for your answer,
As expected, alpha seems to be calculated from kappa [Thermal conductivity] and Cp. I've found kappa being calculated in the sutherland transport model however, this thread seems to hint that this kappa() is not used at all. Can someone who knows a bit more about these models shed some light? I've been in a wild goose chase for some days, and I can't figure this one out |
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