Design Of The Axial Flow Pump Using The Method Of Variable Circulation And Variable Meridional Velocity And The Analysis Of Flows In The Pump

The axial-flow pump is a type of impeller pump featured by relatively high specific speed.Because of its capability of transporting liquid medium with high flow rates,the axial-flow pump has been used widely in important projects,such as in pumping station and flood control engineering.Regarding small-scale axial-flow pumps,the manufacture,as well as the installation and adjustment,is convenient.In contrast,for large-scale axial-flow pumps,more specifically,the axial-flow pump with fully adjustable blades,the pump performance cannot be easily guaranteed through mere design and calculation.Therefore,the model design plays an important role in the design of the large-scale axial-flow pump.In the present study,the design with variable circulation and variation meridional velocity was implemented based on the lift method.With the NACA16 foil,the model design was performed for a fully-adjustable axial-flow pump with the specific speed of 930 and the inlet diameter of 1800 mm.The computational fluid dynamics(CFD)technique was used in the design of the hydraulic components;hence,the flow mechanisms associated with the model pump were analyzed,providing a reference for the hydraulic design.The design result was validated via the model pump test.Strength examination was performed for the major components of the prototype pump;after that,the prototype pump was manufactured and put into service.Major works in the dissertation are following:(1)The fundamental principles underlying the method of variable circulation and variable meridional velocity were analyzed.The design scheme was validated for the fully-adjustable axial-flow pump.The hydraulic design of the model pump was performed.The flows in the model pump were simulated using CFD technique and the results were analyzed;then,the design scheme was determined.(2)The performance test was conducted for the model pump.A test rig,with an open loop,was built for the model pump.For blade angles of-4°,-2°,0°,+2° and +4°,the performance of the model pump was obtained.An evaluation of the pump performance within the whole operation range was attained.(3)Based on the determined model pump,the dimensions of the prototype pump,with fully adjustable blades and an inlet diameter of 1800 mm,were obtained through similarity laws.A comprehensive examination of strength for the chief components of the prototype pump was performed via the analysis of the forces exerted on the components.The structural performance of the prototype pump was verified.The prototype pump was manufactured.In the present study,the method of variable circulation and variable meridional velocity was practiced.A systematic strategy incorporating the design of the model pump,flow simulation,the test of the model pump,similar transformation and the examination of the strength of the prototype pump,was proposed.Flow characteristics were described with numerical simulation;performance of the pump for various blade angles was examined with the model test;Major influential factors underlying the operation stability of the large-scale pump were explained through strength examination.Moreover,such a strategy was used in the fully adjustable axial-flow pump with an inlet diameter of 1800 mm.The favorable effect of the strategy is proven.The prototype pump is still in service and the performance of the pump meets all the specified requirements.