Analysis And Research On Hydraulic Optimization Design And Pressure Fluctuation Characteristics Of Mixed Flow Pump

Mixed flow pump is a kind of water pump widely used in all walks of life and plays an important role in the development of the national economy.With the rapid economic development and the increasing urgency of the global energy crisis,the requirements for mixed flow pumps are also increasing.Traditional design methods mainly aimed at improving hydraulic performance have become increasingly unsuitable,It has become mainstream to use CFD numerical simulation technology to optimize the pump’s energy characteristics and operating stability by performing steady and unsteady constant value simulations on mixed flow pumps.In this paper,a guide vane mixed flow pump is taken as the research object to optimize its hydraulic performance,impeller radial force pulsation and pressure pulsation at the pump outlet.Firstly,CFD numerical simulation technology is used to predict the performance of the original pump model.The internal flow field analysis method was used to analyze the causes of its insufficient performance,and on this basis,the impeller and guide vanes were optimized.Steady numerical simulation of the optimized model is carried out,and the performance,internal flow field and axial force are compared and analyzed with the original simulation.At the same time,to study the influence of the relative position of the guide vane inlet edge on the performance of the mixed flow pump,the angle between the impeller outlet edge and the guide vane inlet edge is defined asα,and four different angleαguide vane schemes are selected to perform unsteady numerical simulation and Spectrum analysis.The spectrum analysis of the impeller radial force pulsation and pressure pulsation of the pump model before and after optimization is carried out,and the pressure pulsation coefficientλis introduced to quantitatively analyze the pressure pulsation at the pump outlet.The research shows that the internal flow field analysis method can be used to optimize the hydraulic performance of the pump.Compared with the original model,the hydraulic performance of the optimized model is significantly improved.Under rated conditions,the optimized head has increased by 12.34%,the efficiency has increased by 2.02%,and the axial force has only increased by 944N.At 1.2Q_opt,the optimized head is increased by92.82%,and the efficiency is increased by 66.70%.The relative position of the inlet edge of the guide vane has a great influence on the energy characteristics and pressure pulsation of the mixed flow pump.Whenα=5°,the hydraulic performance of the mixed-flow pump is the best.As angleαincreases,the amplitude of pressure pulsation fluctuations at the inlet and outlet of the impeller and inside the volute becomes smaller,and the pressure pulsation in the volute near the volute tongue is less affected by the rotation of the impeller and larger affected by the volute tongue,but there is no obvious law on the influence of the main frequency amplitude.The impeller radial force pulsation of the optimized model is significantly smaller than that of the original model.Quantitative analysis of the pressure pulsation at the pump outlet showed that the pressure pulsation of the original model was31.4%,and the optimized model was 4.7%,a decrease of 108%.