
FLUENT adds contributions due to mass transfer only to the momentum, species, and energy equations. No source term is added for other scalars such as turbulence or userdefined scalars.
Let be the mass transfer rate per unit volume from the species of phase to the species of phase . In case a particular phase does not have a mixture material associated with it, the mass transfer will be with the bulk phase.
Mass Equation
The contribution to the mass source for phase
in a cell is
(23.71) 
(23.72) 
Momentum Equation
For VOF or mixture models, there is no momentum source.
For the Eulerian model, the momentum source in a cell for phase
is
(23.73) 
(23.74) 
Energy Equation
For all multiphase models, the following energy sources are added.
The energy source in a cell for phase
is
(23.75) 
(23.76) 
Species Equation
The species source in a cell for species
of phase
is
(23.77) 
(23.78) 
Other Scalar Equations
No source/sink terms are added for turbulence quantities and other scalars. The transfer of these scalar quantities due to mass transfer could be modeled using userdefined source terms.