Effect of the staggered impeller on reducing unsteady pressure pulsations of a centrifugal pump

The emitted noise and vibration induced by the unsteady flow of the centrifugal pump are always focused during its running, which is also associated with the high amplitude pressure pulsations. How to reduce pressure pulsations remains a crucial problem for the researcher considering low noise design of the centrifugal pump. In the current research, a special staggered impeller is proposed to reduce intense pressure pulsations of a centrifugal pump with n(s )= 69 based on alleviating rotor-stator interaction. The numerical simulation method is conducted to illustrate the influence of staggered impeller on the pump performance and pressure pulsations, and three typical flow rates (0.8CYRILLIC CAPITAL LETTER EFN-1.2CYRILLIC CAPITAL LETTER EFN) are simulated. Results show that the staggered impeller will lead to the pump head increasing, and at the design working condition, the increment reaches about 3% compared with the original impeller. Meanwhile, the pump efficiency is little affected by the staggered impeller, which is almost identical with the original impeller. From comparison of pressure spectra at 20 monitoring points around the impeller outlet, it is validated that the staggered impeller contributes significantly to decreasing pressure pulsations at the concerned working conditions. At the blade passing frequency, the averaged reduction of 20 points reaches 89% by using the staggered impeller at 1.0CYRILLIC CAPITAL LETTER EFN. The reduction reaches to 90%, 80% at 0.8CYRILLIC CAPITAL LETTER EFN, 1.2CYRILLIC CAPITAL LETTER EFN, respectively. Caused by the rib within the staggered impeller, the internal flow field in the blade channel will be affected. Finally, it is concluded that the proposed staggered impeller surely has a significant effect on alleviating intense pressure pulsation of the model pump and does not obviously alter the global performance of the pump, which is very promising during the low noise pump design considering its feasibility for manufacturing.