Blade Cutting Influence on Centrifugal Pump Noise Reduction

A centrifugal pump with a specific speed ns = 67 is considered in this study to investigate the impact of blade cutting (at the outlet edge) on the fluid-induced noise, while keeping all the other geometric parameters unchanged. The required unsteady numerical calculations are conducted by applying the RNG k-epsilon turbulence model with the volute dipole being used as the sound source. The results indicate that the internal pressure energy of the centrifugal pump essentially depends on the blade passing frequency and its low-frequency harmonic frequency. Moreover, the pressure pulsation distribution directly affects the noise caused by the centrifugal pump. The sound pressure inside and outside the centrifugal pump and the sound power at the blade passing frequency gradually decrease increasing cutting distance of the impeller blades. When the cutting percentage is 1.21%, that is, the clearance ratio between impeller blade and tongue is 8.57%, the comprehensive performance of the centrifugal pump is the best.