Defining Cp as a function of temperature and pressure
 

Hi all,

I do analysis of c-d nozzle with R245fa organic fluid and the fluid is in super-critical region at inlet. Then, the fluid is in vapor region.

I can define specific heat constant (Cp) as a function of temperature, but it depends on pressure also.

For example, At 432 K (which is my inlet total temperature), Cp is 1.095 kJ/kg-K at 1 bar, it increase up to 3.365 kJ/kg-K at 37 bar which is in supercritical region.

I don't know how to define Cp as a function of T and P. I searched but I couldn't find that I want.

If it is not possible, which pressure value should I use as a constant to define Cp only as a function of temperature, ?

UDF is possible

https://www.cfd-online.com/Forums/fl...ific-heat.html

http://www.afs.enea.it/project/neptu...udf/node51.htm

This option is not available with the premixed, non-premixed and partially premixed models, and should be used as a compiled UDF only.

Hi,

I'm having a similar problem and I would like to know if this issue has been solved. If so, how was it solved? Thank you.

Thank you KaLium. I have just seen this message, sorry for late reply.

I couldn't define Cp as a function of both T and P. I selected an average pressure value and I define Cp only depends on temperature for my graduation project. @estevaotolentino

Ok, I got it. Thank you for the reply.