Reply To: Energy source term related with chemical reaction in UDF

[Rob]

Chemicals have a formation energy, but also energy associated with state. In Fluent these two components are lumped together as enthalpy. That's fine for separate models with reactions OR phase change but can be a little messier when it's AND. So, use some caution. 

I assume your reaction is actually A = B + C + energy?  The energy term will come from the enthalpy. However, you're also adding and removing mass from the domain against a reference of 298.15K so will need to add and remove heat from the phases. 

Do A and C mix? Ie is the liquid a species mixture or two separate phases? 

R19.2 is around 5 years old now, and multiphase saw significant improvements in the 2019-2021 period that will make a difference. Changes since are equally useful but may be less obvious.