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August 6, 2012, 06:58 
implementation of wallHeatTransfer BC

#1 
Senior Member
Tobias Holzmann
Join Date: Oct 2010
Location: Leoben (Austria)
Posts: 1,395
Blog Entries: 5
Rep Power: 24 
Hi all,
i have a question to you. I am using the flamelet solver build by Alberto Cuoci et. al. All variables are depended on the mixture fraction Z in that solver. There for you just have to solve the navierstokesequations (p & U) and two additional equations describing the mixture fraction Z and the variance of it Z". Thats all. With Z and Z" you go into a lookuptable and extract your values like, cp, T, h, and so on No energy equation is solved! The extension by Alberto is using the enthalpy defect. Therefor he is solving an additional enthalpy equation H (its not the enthalpy h). You can use zeroGradient or fixedValue temperature BC but a wallHeatTransfer BC is treated like a zeroGradient BC. If you have a fixedValue you calculate the enthalpydefect from that temperature. Thats a other way then in the inside cells or on a zeroGradient BC. The idea is to implement a wallHeatTransfer to make the "fixedValue BC" more dynamically... The problem is the following. I implemented the BC and now I can use the wallHeatTransfer BC but its like a fixedValue BC couse I am not solving the transport equation for "h" and do not get into the updateCoeffs() function. If I implement an additional enthalpy equation for "h" its working but the calculated "h" field is not the same like "H" depend on the difference species and therefor the temperature field I get is wrong. Is it possible to add the BC without solving the enthalpy equation? Therefor I should get into the "updateCoeffs()" function or? Hmm I think its hard to understand couse that solver is very complex and the thermodynamics too. Maybe someone has a suggestion?! Thanks for ready also. Tobi 

August 8, 2012, 08:21 

#2  
Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 9,531
Blog Entries: 39
Rep Power: 97 
Hi Tobi,
I was about to answer your private message and remembered to come look for a thread of yours on this... and since I found it, I'll reply to it here. Quote:
In the Doxygen description for this method you'll see an entry in the section "Referenced by" to fvPatchField< Type >::evaluate(), which is also part of this very same class template, namely: Code:
void Foam::fvPatchField<Type>::evaluate(const Pstream::commsTypes)
This is how I did this trip (fully based on the Doxygen generated code documentation):
So the next question will be: then who calls "evaluate"? Best regards, Bruno
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