[aminhgn]

Hello,

I am trying to use UDF to define my properties. The problem is 2 phase flow (Liquid Desiccant-humid air). Since both flows are the mixture, I want to use define properties for the liquid desiccant flow but by define_properties loops over all cells. I want to loop over only liquid desiccant solution. for example for calling species which C_YI (c,t,0), I want to apply on liquid desiccant phase.

Thank you,
Amin

[vinerm]

Are you using multiphase or species model or do you have both multiphase and species modeling enabled? As far as multiphase is concerned, each phase has its own property dialogue box. If you use a UDF, though it goes over each cell but Fluent ensures the properties of only that phase are changed to which UDF is hooked.

[aminhgn]

Originally Posted by vinerm

Are you using multiphase or species model or do you have both multiphase and species modeling enabled? As far as multiphase is concerned, each phase has its own property dialogue box. If you use a UDF, though it goes over each cell but Fluent ensures the properties of only that phase are changed to which UDF is hooked.

Thank you for your kindly reply. My problem has been solved. I only have one more problem, I want to use DEFINE_SPECIFIC_HEAT to define my cp based on concentration and temperature. this function is :

DEFINE_SPECIFIC_HEAT( name, T, Tref, h, yi)
which i can use T instead of C_T function but what about C_YI which is concentration? How can I get my concentration in my function?



Regards,

Amin

[vinerm]

In almost every (with few exceptions) DEFINE_ macro, it's only the first argument, i.e., the name of the function, that Fluent expects from the user. The values for the other ones are supplied by Fluent. So, you do not need either C_T or C_YI. Those values are already there in T and yi. You can use yi as it is. Do note that it is a vector, i.e., yi[0] will give mass fraction for the first species.