Entopy generation in CFX
 

I need to find the entropy generation in a channel with heaters in the CFX. Because the program does not calculate the entropy generation, I've decided to make a new approach: I've collected the speed and temperature gradient data generated by CFX, calculated the entropy generation at each point and then I took the entropy generation mean value. This approximation is valid? What are the other ways to find the entropy generation? How can I introduce the entropy generation PDEs in CFX? I know that I can do this by creating a FORTRAN routine, but I haven't found where do I write this routine in CFX.

I know this subject has already been discussed in this forum, but I looked for this and haven't found any answer about it.

Thanks again in advance :p