Learning Forum

[Jiacheng lyu]

I hope to define the Pre-Exponential Factor  of a chemical reaction as a function of the current substance concentration. Therefore, I need to get the mass concentration of a certain substance I need from fluent, and then define the pre-exponential factor through the functional relationship. Hope to get detailed answers and examples.

[Rob]

There doesn't look to be a hook in that panel for that, I know it's been asked before so check (search) on here. 

[Jiacheng lyu]

Maybe UDF is a method. Can you provide relevant examples? I couldn’t find any relevant useful answers before.

[Rob]

I can only point you at the UDF documentation; you may find you need to write the whole chemistry model. I did raise an enhancement request last time this was requested, but I can't share any updates on that. 

[Jiacheng lyu]

I want to input the numbers in the panel as a function related to oxygen concentration, but under the current settings I can only input numbers。

[Rob]

Correct. Hence you may need to do a lot more coding at present. 

[Jiacheng lyu]

Hello, can you provide me an example of the code. Do you need to define the entire chemical rate or just Pre-Exponential Factor?

[Rob]

Double check the Fluent theory to make sure it's not doing what you need, but otherwise you may find  DEFINE_VR_RATE or DEFINE_NET_REACTION_RATE to be of use. There will be examples using both macros in the UDF manual. 

[Jiacheng lyu]

Thank you for your reply