Abstract:Centrifugal pumps are widely used to deliver liquid media in agriculture, pharmacy, industry, etc. Compared with the case delivering pure liquid such as water, centrifugal pumps not only have lower efficiency but also are subject to severe vibration, noise and erosion when delivering cavity two-phase flow. In order to further improve the cavitation performance of low specific rotation centrifugal pump, a method of making the blade slotted to control cavitation in a centrifugal pump was proposed. The slotted impeller blade near the inlet of centrifugal pump was studied. According to the flow characteristics of cavitation in centrifugal pump and the cavitation dynamics model of Kubota cavitation model, the SST k-ω model was used to simulate and analyze the two-phase flow in a centrifugal pump under the same working conditions. The simulation results showed that after the blade surface was slotted, the head of the centrifugal pump was increased, and the head of the centrifugal pump was increased by 12.8% at the design point, and the efficiency was increased by 4.2%. The slotted blade can effectively prevent the low pressure region from expanding outward, change the pressure distribution and inhibit the cavitation in every stage of the centrifugal pump. The slotted blade can optimize the flow field structure, increase the pressure in the flow channel and reduce the volume fraction of the cavitation. The cavitation volume of centrifugal pump impeller in every stage of cavitation was smaller than that of impeller without slot when the blade was slotted. In the stage of cavitation development, the volume of slotted space-time bubble continued to decay.
