In user subroutine-----'sorent.f', we specify source term for enthalpy. So we difne 'sh'----- sorce term, wich is on the right hand of the heat transfer equation, don't we?

However, in the help it said "Energy sources or sinks, due to exothermic or endothermic chemical reactions, respectively, are implicitly allowed through the definition of h"

What dose "implicitly allowed through the definition of h" mean? Is it said that actually, we define the fluid enthalpy ----- 'h' as sorce term in user subroutine? Or we just difine sorce term 'sh' in the form of enthalpy 'h'? It confuse me.

Thank you for your reply. However,what does *NM* mean?