Problem´s results with pressure as inlet cond.

Hi

I´d like to ask if these results are standard for my setting. My task is: set fix inlet pressure, have fixed flow (outlet) trough the pump and get outlet pressure and (dif. pressure out-in). I know that it work well inlet-flow outlet-pressure, but I need to use the first setting with cavitation option.

I did simple test with rotating impeller and changed only conditions at inlet/outlet - flow/pressure without cavitation option.

I´ve got diferent results and in case "inlet-pressure" outlet flow is different of inlet flow, but both are green.

I did next test with changing cond. only for pipe (without rotating part) and the results were both OK.

Could you tell me what mistake(s) I (probably) did?

Results are shown here. Attached file is in better quality. 

Thanks

Michal 

SolidworksFlow Simulation