In article <firstname.lastname@example.org>, Evgeny wrote: > Prompt how correctly to set Centrifugal Pump parameters. > > I use "By two 1D characteristics". > > Parameters Q-P [0 0.02 0.04 0.06 0.08 0.1 0.12] m^3/s > Pressure P [4.4 4.8 5.2 5.2 4.8 4 2.4] atm > > Parametres N-Q [0 0.02 0.04 0.06 0.08 0.1 0.12] m^3/s > N [2800 3100 3600 3900 4200 4800 5000] W > > Reference density 1000 kg/m^3 for water as I understood > > Reference angular velocity 3000 rpm > > I submit on an input 3000 rpm and it should turn out Q ~ = > 0.07 m^3/s at the expiration in atmosphere and P ~ = 4.4 > atm at the closed orifice. > > I have hydraulic flow rate turns out negative (((( > Around here we do lots of hydraulic modelling/simulation in Simulink (although we use our own models, not SimHydraulics - but the principles are the same).
Just because the pump will generate a positive head at the set speed does not mean the flow will necessarily be forwards. What about the pressure differential across the pump in the service conditions? If back-pressure-differential (outpet pressure less suction pressure) exceeds the pump head, then the flow will go backwards.
I don't know how good the pump modelling is in SimHydraulics; but a complete pump model should have a characteristic in all four quadrants of the head/flow curve (all combinations of +/-ve head and flow).