Convergence problem
 

Hello all. I'm modeling a 2-D diffusion chanel of a centrifugal compressor and encountered problems in convergence. In order to simplify the model I had set only 2 (non-wall)B.C.: Mass-flow/Pressure Inlet, Pressure Outlet. To further simplify I tried using Laminar Viscous Model, material is Water-Vapor (Density: Ideal gas. Viscosity: Sutherland),First order up wind, Coarent no' 0.1. I need advise, how can I encourage convergence. Thanks in advance. For more details, nahariziv@gmail.com .