Enthalpy to temperature
Hi all,
I am new to OpenFOAM. I was looking at where OpenFOAM does the h to T (or hs top T) conversion, and I noted that they use a Newton iteration mthod. But when I try to trace the sepcific heat they use in this equation, they seem to use Cp=Cp(T) and not Cp=Cp(T,Yi). This is the file I am talking about: $FOAM/src/thermophysicalModels/specie/thermo/janaf Can anyone confirm/explain this? Thanks in advance. 
h to T conversion
Hi,
I have exactly the same question. Thanks Farshad 
Enthalpy to T
I have dug deep since this post, and have the answers. When they go for the h>T conversion they hold the composition fixed, and define a new 'gas' with the composition averaged thermal properties. It is the Cp of this mixture gas that is (rightly) used to compute T.

Hi all,
I am looking for the extract of the code where the conversion from h to T is done but I do not find it. Can anybody tell me where it is? 
Check under
Quote:

Thank you very much. I found the iteration in these lines:
// return the temperature corresponding to the value of the // thermodynamic property f, given the function f = F(T) and dF(T)/dT template<class thermo> inline scalar specieThermo<thermo>::T ( scalar f, scalar T0, scalar (specieThermo<thermo>::*F)(const scalar) const, scalar (specieThermo<thermo>::*dFdT)(const scalar) const ) const { scalar Test = T0; scalar Tnew = T0; scalar Ttol = T0*tol_; int iter = 0; do { Test = Tnew; Tnew = Test  ((this>*F)(Test)  f)/(this>*dFdT)(Test); if (iter++ > maxIter_) { FatalErrorIn ( "specieThermo<thermo>::T(scalar f, scalar T0, " "scalar (specieThermo<thermo>::*F)(const scalar) const, " "scalar (specieThermo<thermo>::*dFdT)(const scalar) const" ") const" ) << "Maximum number of iterations exceeded" << abort(FatalError); } } while (mag(Tnew  Test) > Ttol); return Tnew; } There is something I do not understhand. What does “this>” means? 
I might be wrong but I don´t think this is an OFspecific function.
Ecosia (instead of googling it) "this pointer" or "this pointer c++" or such. Tibo 
It is a C++ keyword. "this" acts like a pointer to the object whose member function is under consideration.

Dear friends,
I have another doubt about these files. Where are defined the functions F and dFdT? 
They are the function and its derivative.
The Newton iteration in this case calculates T, given F(T) and dF/dT(T). The function gets pointers to the functions F and dF/dt. If the energy variable is enthalpy h, then F=h(T) and dF/dt=Cp(T). If it is internal energy e, then F=e and dF/dT=Cv(T). The code resolves these at runtime, and sends the appropriate pointers to the Newton iteration routine. 
Dear friends,
Thank you very much for your help. I need to simulate melting of a solid. In that case, the enthalpy is given by the following equation: http://fotos.miarroba.es/lamasgaldo/4energyequation3/ http://fotos.miarroba.es/lamasgaldo/4energyequation3/ http://fotos.miarroba.es/lamasgaldo/...3/#anchorPhotohttp://www.cfdonline.com/Forums/[im...3/#anchorPhotohttp://fotos.miarroba.es/lamasgaldo/...3/#anchorPhoto http://fotos.miarroba.es/lamasgaldo/...equation3.jpg http://fotos.miarroba.es/lamasgaldo/3energyequation3 http://fotos.miarroba.es/th/32d6/204...2D4F3CD61F.jpg where L is the latent heat and alpha_l the mass fraction of the liquid phase. How do I implement the term alpha_l*L in the functions F and dFdT? 
Hi,
I would use Code:
F=H And, at that point you will typically hold the composition fixed, so that \alpha, L and H_{ref} are fixed. So, dFdT=Cp. This of course assumes that L is not a function of T. 
A Little question?
Hi, I have a little question,
I understand that if i.e, the energy variable is enthalpy F=h(T) and dF/dT=Cp(T), my question is in where it is defined in the code that F and dF/dt take these variables as arguments. Thanks in advance. 
Enthalpytemperature for melting problem
Hi isabel ,
Will you please guide me how you implemented the melting problem ? thanks in advance. Quote:

function "f"
Hi All,
I just don't know where that "f" is coming from in OpenFOAM??? I know "F" and "dFdT", but I don't understand "f" in the Newton's routine!! Quote:

Newton's Routine
What is that "f" in the routine?! Where does it come from?
Quote:

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