i don't know about pump case. I know rpm of blade and would like to know volume flow rate. what boundary that are specificed at inlet and outlet? I don't kown pressure at inlet,too. Thanks

try pressure pressure both at atmospheric

Do you know the head generated by the pump? Then you can specify 0 pressure at inlet and <head, Pa> pressure at outlet. But such probems are difficult to converge.

Hi Anton, and Everybody.

I have a question to you guys. You mean If I know my pump's outlet pressure value, I just specify inlet pressure as 0, environment off, and outlet pressure, let's say 0.5MPa. Also, could you please explain the difference between "ENVIRONMENT ON" and "ENVIRONMENT OFF"? If I specify inlet pressure as "0" what exactly does it mean (the physical meaning)?

Really appreciate your help

Regards

Environment oprion make sence only for "pressure inlet" boundaries, its idea is to account for "entrance losses", i.e. the pressure specified will be equal to total pressure.

As for the numbers, you have to remeber that you specify relative pressure (relative to "reference pressure"). So if you specify 0 Pa this means that the absolute pressure will be equal to one specified as reference pressure, when you specify 0.5MPa - absolute pressure will be reference pressure + 0.5MPa. By default reference pressure is 0.1MPa (atmospheric pressure)

Thank you very much Anton for very clear explanation.

Regards

I input 0 inlet pressure and out pressure, But it doesn't flow, velocity's inlet and outlet boundary is 0 m/s. I set pizo pressure, envalument on and mean on of both boundary. Do you have any ideal? Thank you

Turn off environment - you can't use environment and mean options together

you mean setting inlet and outlet boundarys are pizo , enviroment off and mean on. Or another?

Yes. But actually there is no 100% guarantee that you'll get a solution this way, because pressure-pressure problem is not well posed. The alternative way is to solve a number of problems with inlet-outlet boundary conditions. You can specify different flow rates at inlet and calculate a head vs. flow rate curve (performance curve). Then you can find a point of your given head and get a corresponding flow rate