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-   -   DEFINE_PROPERTY udf question (http://www.cfd-online.com/Forums/fluent-udf/47254-define_property-udf-question.html)

Erik February 6, 2008 13:49

DEFINE_PROPERTY udf question
 
I want to preface this by saying that I'm relatively new to using fluent and I have not written any udfs to date.

With that said, does anyone have an example of how to write a DEFINE_PROPERTY udf? I'm modeling liquid-liquid combustion using dense gases (I'm purposely neglecting droplet formation/vaporization for simplicity) and I want to specify liquid densities for my reactants (from a temperature dependent lookup table) and have fluent use the ideal gas law to calculate the density of the products. Has anyone out there done this before? Can you provide me with any pointers on how to do this?

Thanks,

Erik

NRD February 17, 2008 11:11

Re: DEFINE_PROPERTY udf question
 
My response might not answer your question directly, however, I just thought of sharing my experience.

I had been trying to write an UDF to account for the variable density of water using an equation of state. I realized that if we want to calculate density using DEFINE_PROPERTY you need to redefine speed of sound also. You will find an UDF related to this in the DEFINE_PROPERTY section of the FLUENT UDF manual. Let me know if you have questions on my implementation.

hw0076 September 4, 2012 04:10

Hi,NRD,may I ask a question about property UDF,I want to define a user-defined viscosity and thermal conductivity, so is there other restrictions in other properties?
I set the density as ideal-gas,and i can't choose udf for option for viscosity and thermal conductivity,do you know why?
Thank you!


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