how chtMultiRegionFoam calculates the convective heat transfer coefficient
I was wondering about something and I thought of posting it here, in case somebody already knows and wants to share.
I use the solver chtMultiRegionFoam and I would like to discuss in my report how the solver (or the BC?) calculates the convective heat transfer coefficient (h or α). My problem is strongly defined by this parameter and since the calculation is based on empirical relations ( and there are a few), it would be good to know.
thanks a lot
convective heat transfer coeffiecient
i think it calculates it from nusselt number specified in one of case system files and conduction coefficient K specified in thermoproperties file.
thanks a lot for your answer! do you know where exactly we specify the Nusselt number?
all the best
convective heat transfer coefficient
prantle number is specified in file thermoPhysicalProrerties file in path:
and in same file in topAir.
then nu=a Re^b Pr^c.
then nu= h/K.l,
K: is specified in same file belong heater and solid areas.
in this way h could be calculated.
you are awesome
thank you very much!
Sorry to intervene, just a question: Do you know where h is calculated or used in the code?
The multiRegionHeater tutorial for example uses "compressible::turbulentTemperatureCoupledBaffleMi xed" as BC.
Checking the code in src/turbulenceModels/compressible/turbulenceModel/derivedFvPatchFields/turbulentTemperatureCoupledBaffleMixed, I see that the only thing happening is to impose continuity of temperature and conductive heat flux on the boundary.
But I may be wrong, I have been wrong plenty of times before :-)
very interesting. Can you elaborate a bit more please? where exactly is the temperature continuity imposed?
Hi giorgos and dear Foamers,
sorry giorgos it was along time from your post, i reviewed your post again and recently, i began with chtMultRegionFoam so i reviewed the tutorial case and boundary condition.
firstly, about heat convective coefficient, if you want to put it as input in your case there is no need to do this. if you reviewed the energy equation (which solver uses) you will find that only temperature, velocity, properties of solid and fluid are required. heat transfer coefficient in required as input if solver uses correlations which isn't applied in over solver.
secondly, if you want to get the overall coefficient based on temperature distribution gotten from your solver, i think there is a command you can use (you may have to search to get it).
finally, I'd like from you and anon_a to discuss this post with me. it was useful for me last time to get your feed back to re-review the case.
good luck, :)
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