Research On The Performance Improving In Low Specific Speed Centrifugal Pump With Slot Blades

In human production and life,centrifugal pumps can be seen everywhere,but the efficiency of low specific speed centrifugal pumps is very low and as the impeller inlet pressure decreases,the centrifugal pump will cavitation,resulted in a significant reduction in the lift,the centrifugal pump will not be able to work,so improve the hydraulic performance and anti-cavitation performance of the low specific speed centrifugal pump is of great significance for the efficient operation of the centrifugal pump.Previous studies have proved that a reasonable slotted position(designed based on flow control ideas)can reduce the energy loss of high-speed compressors.So far,there have been many researches on the application of slotted technology on centrifugal compressors and fans,there have been few studies on centrifugal pumps.Based on the relevant researches of scholars at home and abroad,this paper uses the numerical simulation method to deeply study the application of the slotted technology on the low specific speed centrifugal pump;the internal flow of the low specific speed centrifugal pump(slottedd blade type)is carried out.The numerical simulation and experimental verification work to explore the mechanism of slotted the blade surface can improve the hydraulic performance and anti-cavitation performance of the centrifugal pump and hope to provide reference for the design of the centrifugal pump.This article will study from the followed aspects:1.Introduced the research status of domestic and foreign scholars on the application of slotted blades in rotating machinery.Research on the application of slotted blades in rotating machinery by domestic and foreign scholars includes: research on slotted treatment on the cover of centrifugal compressors,indicated that slotted can improve its flow resistance;application of slotted technology can make impellers.The flow characteristics of the trailing edge flow field are effectively improved and the stability of the flow field is improved.2.Based on the analysis of the original model and the steady results of six kinds of slotted models,the mechanism of improved the flow inside the impeller flow channel and improved the cavitation performance of the slottedd blade is explored.The flow separation at the blade slotted is analyzed.The effects of pressure,flow field,turbulent kinetic energy and vacuoles.The study founded that opened a rectangular slotted of 1 mm × 1 mm at 45% of the impeller radius can improve the lift and efficiency of the centrifugal pump;the vortex structure is destroyed,so that the fluid at the front end of the pressure surface of the blade will maintain the original flow tendency,thereby reduce separation of the boundary layer increases the load on the pressure surface of the blade and effectively prevents the low pressure region from expanded outward.In the stage of cavitation development,the volume of the vacuole in the centrifugal pump impeller is significantly smaller than that in the original model,cavitation development has been effectively suppressed.3.In order to study the mechanism of the performance of the centrifugal pump to improve the performance of the centrifugal pump,the unsteady calculation of the original model and the six slotted models was carried out to study the transient characteristics of the slotted flow field structure,bubble growth rate and pressure pulsation impact.The results showed that proper blade slotted can stabilize the flow inside the impeller and improve the operating stability of the centrifugal pump in the whole working condition.The mechanism improved the performance of the centrifugal pump is that the slottedd blade changes the velocity field inside the impeller.To make the velocity distribution uniform;during a period of impeller rotation,the volume of the void in the slotted model is much smaller than the volume of the void in the original model,because the pressure near the slotted is relative to the pressure of the original model.High pressure prevents the growth of vacuoles.4.The numerical simulation results of the low specific speed centrifugal pump(blade slotted)with splitter blades showed that the proper blade slotted is beneficial to improve the performance of the centrifugal pump and the slotted design of the low specific speed centrifugal pump.A reference is provided.When designing a low specific speed centrifugal pump with splitter vanes,a slotted can be designed on the blade and a vertical slotted of 1 mm × 1 mm is opened at 45% of the radius of the impeller.