How to define Cp using UDF?
 

I am using FLUENT 6.1 to model solidification process. Since FLUENT can not define thermal-physical properties seperately for solid/liquid, I have to use UDF to realize the task. However, there is no "user defined" option for Cp. I don't know why and want to know how to define Cp for solid and liquid seperately. Any suggestions will be appreciated very much!

Re: How to define Cp using UDF?
 

Try to use DEFINE_PROPERTY and define Cp. Once complied, link the defined Cp to the material property.

Re: How to define Cp using UDF?
 

Thanks for your reply. I was trying to do so. I can do this for density and conductivity, but this doesn't work for Cp, since there is no "user defined" option in the dropping list for Cp. I don't really know why there is no "user defined" option for Cp. Any further advice will be appreciated!

Re: How to define Cp using UDF?
 

According to Fluent user's guide, "UDFs cannot be used to define specific heat properties; specific heat data can only be accessed and not modified in FLUENT." So I think you should use the mixture model or something using species (one for liquid phase and one for solid phase). Hope it will help you.

Re: How to define Cp using UDF?
 

Hi,

You have to customize the real gas model. Otherwise,you can't do that even via UDF in usual way.

Thanks,

This might be too late i guess
 

but this is how you have to define specific heat using a UDF
DEFINE_SPECIFIC_HEAT(Cp, c, t)

hope it helps either you or someone else who stumbles on to this thread.