Moving solid problem
 

I'm trying to model solid particles flowing through a cylindrical pipe (by means of an archimedes screw that is not modeled). Specifically, I need to model the thermal effects. Steam at the dew point is also fed in with the solid particles.

There are two ways that I thought of that might be able to accomplish this

a) Model the solid particles as a super viscous fluid, with a porosity to steam

b) Model the solid particles as a single solid element that moves along the length of the pipe. Solid would be porous to team, and the solid at the inlet would have to be continually replaced.

Are either of these methods possible? If something is unclear, let me know.