Numerical simulation of complex flow structures and pressure fluctuation at rotating stall conditions within a centrifugal pump

Rotating stall contributes to global oscillation vibration problems, accompanied by noise and possible turbomachinery damage. This study with special emphasis on the vaned diffuser investigates unsteady pressure interaction within pump. A low specific speed centrifugal pump (ns = 69), fitted a is modeled studied. The model performance curve shows characteristic positive slope at 30% of best efficiency point flow rate; 1.0 ?? which attributed phenomena. finite volume method employed computations initialized utilizing shear stress transport k-? before proceeding DDES. Pressure fluctuation velocity magnitude normalized values are used investigate evolution cell generation. root mean square (RMS) (Cp) elicited gain insight into pulsation domain. distinguished “starfish” shape observed for monitor points md1 md20, RMS trend decreasing increasing rate from shut off. Although in channel, an increase along channel toward trailing edge observed, similar trend. propagates ?RS 0.078 0.2 ??, while 0.1 0.087; tends approaching Three distinguishable channels structure five diffuser; entering stall, stalled, recovery stages, channels.