Effects of cutting the blade on the performance and pressure pulsation of a centrifugal pump

Abstract

To solve the severe flow-induced vibration during the pump operation, the impeller cut is a reasonable and operable approach. In the present study, effects of cutting the blade on the pump performance, especially for pressure pulsations, are conducted by experiments, and numerical results are used to discuss the relation between the internal flow and pressure pulsation. Three cutting angles are investigated, and the obtained results are compared with the original pump. Pressure transducers are mounted on the volute wall and outlet to capture pressure signals of different pumps. Results show that at the cutting angle φ = 15°, pump heads at low flow rates are decreased, which are little affected at high flow rates. With the cutting angles increasing to φ = 25° and φ = 35°, cutting the blade contributes to the reductions of pump heads at all the measured flow rates. Pressure pulsations are significantly affected by cutting the blade. For major measuring points on the volute wall, pressure amplitudes at the blade passing frequency fBPF are attenuated by cutting the blade, especially at high flow rates. Mean pressure amplitude at fBPF is decreased by 38.6% at φ = 15°, which is caused by the increasing gap between the tongue and the blade. From comparison, it is suggested that the cut angle φ = 15° can be used to reduce pressure pulsation considering its little influence on the pump head during application. The obtained results will be useful during the pump operation to reduce pressure pulsations by the blade cut approach.