# How is the thermal conductivity calculated?

 Register Blogs Members List Search Today's Posts Mark Forums Read

 May 26, 2016, 07:21 How is the thermal conductivity calculated? #1 Member   Pedro Join Date: Nov 2014 Posts: 50 Rep Power: 5 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; } }``` Best Regards

 May 27, 2016, 10:05 #2 Senior Member   Mahdi Hosseinali Join Date: Apr 2009 Location: NB, Canada Posts: 271 Rep Power: 11 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 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.

 May 29, 2016, 14:33 #3 Member   Pedro Join Date: Nov 2014 Posts: 50 Rep Power: 5 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

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post faizan_habib7 CFX 4 February 1, 2016 18:00 Jared1986 CFX 3 March 20, 2014 11:38 Chander CFX 1 February 29, 2012 18:26 Sas CFX 15 July 13, 2010 08:56 saii CFX 2 September 18, 2009 08:07

All times are GMT -4. The time now is 21:11.