[jessie]

Hello everyone,

I'm facing a problem in modeling a FCC riser. I am using an Eulerian granular multiphase model to simulate the flow pattern. A 3-D, steady state, k-e turbulent, non-reacting, isothermal flow is being simulated using the E approach. There are two phases in the riser right now, gas and solid. There are two different gases flowing into the system from two different inlets and the particle feed into the riser from one of the inlets.

The problem is when I change the drag coefficient relationship between the two gases and the particle from schiller-naumann to syamlal-obrien, the case just diverged. I already tried different meshes and reduced the relaxation factor, however there is no improve at all. The fluent showed "Divergence detected in AMG solver: mp-x-momentum -> Decreasing coarsening group size!......"

If I just use the schiller-naumann, the case can converge. And if I just simulate the flow of one gas and the particle using syamlal-obrien or two gases, at least the case would not be diverged. Does anyone have any idea why this is happening and how can I fix it?

Your help will be appreciated. Prior thanks for your assistance.