Investigation on the effect of impeller slot jet on centrifugal pump performance
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To improve the cavitation performance of centrifugal pump, a new kind of centrifugal pump impeller with slot was proposed. The slot was designed on the impeller shroud near the suction side of the blade leading edge. So, the fluid with high energy in impeller front side chamber was drained to the lowest pressure area. The jet flow would compensate the blade inlet flow certain energy. Based on numerical simulation, pumps inner flow with 5 different slot sizes and their hydraulic performances were compared with the prototype pump. The slot jet would result in the increase of impeller flow rate and volute area ratio, which caused the head decrease within the whole flow rate range. The slot jet can suppress the reverse flow remarkably at low flow rate, and the pump efficiency is improved. The slot jet improves pump cavitation performance effectively, especially at low flow rate. To some extent, the smaller the slot size is, the better pump cavitation performance is. Cavitation performance of the slot impeller with size of 2mm×1.75mm has exceeded the prototype impeller greatly. Compared with the prototype impeller, the lowest pressure near the slot impeller blade inlet and even the pressure of all forepart regions are improved significantly. The slot impeller is proved to be an effective method for suppressing the cavitation, and the available net positive suction head is improved.
Key wordsCentrifugal pump slot impeller slot jet cavitation performance circulation flow
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