Material melted in combustion chamber

Dear All
I am modelling a combustion Chamber, which contains an inflow and outlow.
This means the material enters in solid phase, it warms up and leaves the chamber in liquid phase. I need to have a specified material rate.
But I am not sure which physics are suitable for my case??
I mean for definig the material flow which enters and leaves the chamber in different phases, which physic is suitable??


Any suggestion is highly appreciated.

Regards