[mehdimoradi.]

Hi friends;
have a question;
I want to simulate a process that grains(0.58 volume fraction) are drying with hot air in a hopper continuously. wet grains enter the hopper from its upside and dried grains exit from bottom side of hopper.Hot air enter the bottom side and exit from upside of hopper. Thus we have four ports(2 inlets and 2 outlets). (grains exit with known mass flow rate)
what boundary conditions must be selected to support all of these??
Please help me...