[Weiqiang Liu]

Hi all,

In ANSYS_Fluent_Users_Guide, it says user-defined and user-defined-mixing-law can be used to define thermal conductivity of mixture. The difference between these two methods is that user-defined-mixing-law can specifiy thermal conductivity of individual species. User_Guides also says that if ideal gas law is used, the solver will compute the mixture thermal conductivity based on kinetic theory. Otherwise, mass fraction average of the pure species will be used to calculate mixture species.

I am wondering is the essence of user-defined-mixing-law to define thermal conductivity of individual species in UDF source code and let fluent solver decide mixing law? Actually, User-defined-mixing-law has nothing to do with mixing law. Instead, it's about defining thermal conductivity of individual species?

Best regards

Weiqiang

[vinerm]

You have got it other way around. A user-defined mixing law is to define properties of the mixture, not of the individual species. A mixing law does not apply to a pure material.

[Weiqiang Liu]

Originally Posted by vinerm

You have got it other way around. A user-defined mixing law is to define properties of the mixture, not of the individual species. A mixing law does not apply to a pure material.

Hi, Vinerm,

Thanks for replying. it suddenly comes to me mayby the divergence happened previously when I used generic_property is because I hooked my UDF to user-defiend instead of user-defined-mixing-law.

If I hooked my udf to user-defined-mixing-law, maybe divergenc won't happen anymore.

Best regards

Weiqiang