Particle volume change
 

Hello users
I simulate a metallurgical process on a heater where the phases on the heater are air and (lets say) sand. I decided to use the Discrete phase model to simulate the particles move on the heater as the volume fraction is low(<10-3). After few lab experiments, i saw that the particles density reduce in function with the particles temperature. A the same time the volume of the particles increase. There is no chemical reaction that causes this phenomeno! I have already simulated the air flow in the furnace and i would like to introduce the particles movement. I was thinking of give the density reduction vs temperature by changing the density ( piecewise polynomial) on the particle material properties but im not sure if that would be correct. In my mind, the best solution would be to assume the particle as a bubble that increase its volume vs temperature...
Any ideas please?

I hope i was clear

Panos