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-   -   NSRDS Function-liquid properties (https://www.cfd-online.com/Forums/openfoam-solving/81189-nsrds-function-liquid-properties.html)

arun October 19, 2010 08:54

NSRDS Function-liquid properties
 
I have some questions on the NSRDS functions utilized in OpenFOAM.
For example for vapor pressure determination, there are five scalar values is needed namely, a_,b_,c_,d_ and e_.
These scalar coefficient is listed in the liquid class file for example if I choose C7H16 as my fuel, the scalar values for is given by
pv_(87.829, -6996.4, -9.8802, 7.2099e-06, 2).

Then by using this coefficient the pv values is being estimated using NSRDSfunc1.
The part I don't understand is that why does these coefficient changes during different time step?
Only at first instance of fuel is introduced,these coefficient have same values as given in the liquid class of C7H16.
After that these values changes, why it is so?


Thank you in advance.


A

ENKIME August 14, 2014 18:37

Hello Arun
Hopping you can solve your issue, the coefficiente are used in the pv equation, I recommend to take a look to the Chemicals engeniering handbook From Perry in the subsection of liquid properties you will find the equation that openFoam use and the coefficients.
Kind Regards


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