Actually, the issue we're talking about is the transport equation of the turbulent kinetic energy dissipation rate rather than the TKE equation. So, instead of Eq. [122], you should refer to Eq. [123-124] in the article by Enwald et al. (the same as Eq. (151) in the article by Peirano and Leckner).

The source of dissipation in Fluent theory guide is defined as:

Note that the whole term at the right-hand side of the equation i represents the source term.


In the article, it is defined as

Here, the source term is .


Please read carefully the figures in the last reply, and you can find the details of the derivation and comparison.