Optimum Design And CFD Analysis On Stamping And Welding Multistage Stainless-steel Centrifugal Pump's Impellers

The low-specific-speed stamping and welding centrifugal pump is the specific speed of pump ranged from30 to 60, which is widely used in the field of boiler feed, system of highpurity pure water, medicine, foodstuff,fine chemical industry, fire protection, shipping, high-rise, center air-condition, domestic water, pressureboost and cold-hot water cycle and so on. It's characteristics are low capacity and high head, and has atendency to super-low specific-speed centrifugal pump. The low-specific-speed centrifugal pump has a longand narrow flow passage for its low capacity and high head so as to it found with difficulty. if it ismanufactured by precision casting and bring to low production efficiency, high cost and high rejection ratio.Stamping and welding crafts are used to manufactured multistage stainless-steel centrifugal pump and thesecrafts can effectively solve the problems in foundry casting technique and can be easily mechanized andautomated. The hydraulic performance of stamping and welding pump had advantage of that of foundrypump. The actual design theories and methods for low-specific-speed pump are introduced first,including"the increased flowrate design method", "the method of anti-hump on H ? Q characteristic curve","non-overload design method", "the design method of complex impeller" and so on. According to thesemethods and the characteristic of stamping and welding multistage stainless-steel centrifugal pump, 3 types ofimpellers such as edge type, airfoil type and partly blocked-flow-passage type and so on have been designed.This thesis also describes the numerical simulation of three-dimensional turbulent flow in stamping andwelding multistage stainless-steel centrifugal pump impeller, points out the turbulence model and numericalsolution for it, and gives the writer's view of the grid-generation. According to the distribution of pressure andvelocity on the 3 types of impellers, it analyses and describes the feature of internal flow in stamping andwelding multistage stainless-steel centrifugal pump impeller. According to the study and comparison onefficiency and reliability, the thesis points out merits and faults of the 3 types of impeller, and draws aconclusion that the partly blocked-flow-passage impeller is fit for the impellers of stamping and weldingmultistage stainless-steel centrifugal pump. By simulating the impellers inner flow field, the characteristic ofimpellers inner flow and pump performances are analyzed, This study can be very helpful to improve andoptimize the impeller design.