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Abstract

Based on experimental measurements and flow dynamics analysis, the mechanism of flow separations in the pump flow has been investigated and revealed. The possible flow separation including the rotating stall in the vaned diffuser under the normal flow condition has been confirmed to be merely a diffuser effect and caused by the oversized expansion angle of the diffuser. The dynamics of the part load flow separation of both the stationary and the non-stationary character has been identified to be related to the induced flow circulation at the impeller inlet. The associated flow separation mechanism has been revealed with respect to the build-up of a flow dynamical barrier on the shroud side of the impeller. It exactly explains the coincidence of the flow separation at the impeller inlet and that at the impeller outlet. To quantify the onset of the flow separation, a hypothesis is established based on the revealed mechanism. This has been satisfactorily validated by tests with flow visualizations, pressure measurements and laser doppler anemometry applications. The method for stability control of the pump flows with effective suppression of the flow separation has also been presented.

Keywords

pumps flow separation rotating stall flow dynamical barrier hydraulic barrier LDA

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References

Sinha

Pinarbasi

Katz

The flow structure during onset and developed states of rotating stall within a vaned diffuser of a centrifugal pump. Trans. ASME, J. Fluids Engineering, 2001, 123, 490–499.

Goto

Suppression of mixed-flow pump instability and surge by the active alteration of impeller secondary flows. Trans. ASME, J. Turbomach, 1994, 116, 621–628.

Inoue

Kuroumaru

Yoshida

Furukawa

Short and long length-scale disturbances leading to rotating stall in an axial compressor stage with different stator/rotor gaps. Trans. ASME, J. Turbomach, 2002, 124, 376–384.

D'Andrea

Behnken

Murray

Rotating stall control of an axial flow compressor using pulsed air injection. Trans. ASME, J. Turbomach, 1997, 119, 742–752.

Eisele

Muggli

Zhang

Zh.

Casey

Sallaberger

Sebestyen

Experimental and numerical studies of flow instabilities in pump-turbine stages. 1998Proceedings of the 14th IAHR Symposium Hydraulic machinery and cavitation, 9-11 September, Singapore, 168–175.

Zhang

Zh.

Optical guidelines and signal quality for LDA applications in circular pipes. J. Experiments in Fluids, 2004, 3729–39.

Zhang

Zh.

LDA application methods, 20101st edition (Berlin Heidelberg, Springer Verlag).

Karassik

Messina

J. P.

Cooper

Heald

C. C.

Pump handbook, 20084th edition (New York, McGraw Hill).

Rotating stall mechanism and stability control in the pump flows

Abstract

Keywords

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