Hello, I want to model the mixing of granular media in a reaktor just by flow in the gravity field. Therefor I first want to model the discharge of the reactor (to solve the problem stepwise)! I use the 2d, axissymmetric,unsteady, eulerian multiphase model with 2 phases (air and granular sand)! I've got a time step size of 1e-5 seconds. The Problem is that I always get reverse flow on pressure outlet. Without patching the reactor interior with sand, there is no problem! I think there is a problem with my boundary conditions. what is the real sence of the backflow volume at pressure outlet? I do get enough information about it in the users guide?

Please help me!!!!!

if u r working for a batch case,then set the outlet as pressure outlet and volume fraction=0.0

Thank you for your answer, so far!!!I even have to try this!!!