convergence problem in impingement cooling
 

hello, Am working on a model project involving optimization of different parameters in a jet impingement cooling of a liner(of turbine). I created and meshed the model in icem cfd then imported it to fluent.The model consists of 2 liquid(air) and solid(liner) domain seperately. The impingement is thru a nozzle onto the liner. The temperature on the hotside is 2000F and the inlet air is at 700F. the air enters thru the nozzle(basically a cylinder of dia 1")goes out thru the curved surface (a bigger cylinder of dia 10"). The inlet is velocity inlet with velocity at 200ft/sec. Outlet condn is outflow. turbulence model is kappa-epsilon , realizable with standard wall treatment. The problem is i never get convergence with outlet condn as OUTFLOW, but if it's pressure outlet with no pressure drop then it converges. OUTFLOW is the right boundry condn isn't it. Actually am trying to measure the surface heat transfer coefficient at the impinging surface, pls help thanks for answers

Re: convergence problem in impingement cooling
 

OUTFLOW can be used with inlet velocity for INLET BC, but there are limitations of using OUTFLOW, one of them is that it holds true only if your flow (all parmeters except pressure) has shown no change in them over quite a significant length (example: a fully developed channel flow). Make sure you do not have any geometric change near to inlet. If you have access to V2F model then use this. It should predict better HTC.