
In the case of solidification/melting with species transport, the following species equation is solved:
(24.210) 
where is given by
(24.211) 
Here is the average species mass fraction in a cell:
(24.212) 
and are related by the partition coefficient :
(24.213) 
is the velocity of the liquid and is the solid (pull) velocity. is set to zero if pull velocities are not included in the solution. The liquid velocity can be found from the average velocity (as determined by the flow equation) as
(24.214) 