I am trying to run my model for particle deposition on the wall. I am using discrete phase model with segregated and K-E solvers. The continious phase is air and dispersed phase is polystyrene.I am using group injection with number of particles to be 2000. The point properties which are defined are diameter and mass flow for particles.I am using stochstic technique for particle tracking. For boundary condition I am using Mass flow inlet and pressure outlet(1 atmosphere)for air and have set the boundary condition for wall to be trap(under DPM). My iterations have run for almost 6000 times and they are still continuing showing a lot of cyclic fluctuation. Please let me know what techniques can I use to make my solution converge?

Provided you have good mesh+realistic BC, nothing you can do really. (especially when you work with very high particle flow rate). I suggest you not to judge convergence results from residual error (I bet you won't get residual errors you set). I personally used to judge convergence solution by comparing dpm source (Source (could be momentum,mass,heat etc) transfered to fluid) AND momentum,mass,heat accepted by fluid. If they are balance, you get final solution. How to know source and flux...?it's a bit difficult to explain here, but in general they are on Menu Report...

Good luck.