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-   -   Temperature evaluation with jannaf (http://www.cfd-online.com/Forums/openfoam-solving/59721-temperature-evaluation-jannaf.html)

stephan April 24, 2007 09:17

hi, does anybody know where
 
hi,

does anybody know where the temperature is calculated once the massfraction and the total enthalpy is known?
actually i have the same problem with reactingfoam as some other people in this forum.
Did anybody calculate any usable results with reactingfoam at all?
and if so is it possible to share the case setup?
thanx in advance
stephan

stephan April 25, 2007 07:56

hi, in case somebody else i
 
hi,

in case somebody else is interested:
the function T in specieThermo.C does the calculation of the temperature with given enthalpy and massfractions.
(its seems to be a normal newton iteration..)
stephan

stephan April 27, 2007 11:04

hi, some members of the for
 
hi,

some members of the forum (me too) suggested that there is something wrong with reactingfoam. actually the problem comes up in cases which have too high oxygen concentrations in the beginning.
this leads (especially in cases with one step global reactions) really to temperature which are eventually above 5000K! i never calculated adiabatic temperatures (constant volume or pressure) with really high O2-fractions - so i could not imagine that the adiabatic flame temperature could get so high.
(cantera gives almost the same results - thermo data differs a little bit too)
so at least in my cases the results are just fine - only the setup was "wrong".
nice weekend
stephan


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