I am running simulations on gas-water heat exchanger that take up to 5 days per simulation.  I am hoping to use flow freeze to speed up my calculations so that I can run a parametric simulation in a somewhat reasonable amount of time.  On my last simulation I watched Global goals for pressure and velocity, Velocity fluctuated wildly (+/- 50%) while pressure converged at about the same time as the temperatures.  I believe that if I could isolate the fluid sub-domains the water side pressure/velocity would converge quickly.  My problem is that I do not know how to set goals by sub-domain and, even if I could, I don't believe it is possible to freeze flows in specific sub-domains. 

Has anybody else worked with gas-water heat exchanges and found any tricks like Flow Freezing that can be used to speed up the simulations?

Also, if anybody thinks having the ability to set goals, or freeze flow, a specific fluid sub-domain please vote for the enhancement request I recently submitted (1-8620149566) or let me know if any other ER's have been submitted requesting something similar.

Thanks,