Research On Hydraulic Optimization And Pressure Pulsation Of High Speed Hydraulic Turbine

Further improving the efficiency of energy use is an important link in our country’s path of sustainable development.In view of the direct discharge of a large amount of residual energy wastewater in the industry,pump as turbines are the earliest equipment used for liquid residual energy recovery.It has the advantages of simple structure,low cost and convenient maintenance.However,high speed and partial working conditions have a greater impact on its hydraulic performance and operational stability,so further research on its flow characteristics and operational stability is needed.This paper takes the high-speed centrifugal pump reversely as a hydraulic turbine as the research object,uses UG software to establish its hydraulic model,and optimizes the hydraulic model of the high-speed hydraulic turbine volute by numerical simulation,combined with orthogonal experiment method to optimize the runner blades of a hydraulic turbine.Analyze the pressure pulsation changes inside the model before and after the optimization,and study the pressure pulsation characteristics of the high-speed hydraulic turbine,and finally set up different hydraulic head conditions to study the influence of the bias conditions on the pressure pulsation.From the numerical calculation results,it can be seen that the hydraulic efficiency of the original model is 76.86%,and the hydraulic loss inside the volute and the runner part is relatively large,accounting for 10.6% and 11.5% of the hydraulic loss,respectively.After optimization,the original water inlet pipe of the volute was changed from a straight pipe to a cone.The optimized geometrical parameters of the blade are the wrap angle 77°,the inlet angle39° and the outlet angle 30°.The efficiency of the hydraulic turbine is increased to 81.28%,and the hydraulic loss of the volute and the runner is reduced to 6.79% and 11% respectively.Analyzing the pressure pulsation changes inside the model before and after optimization,it can be seen that the pressure pulsation amplitude of each part of the model has a certain decrease after optimization.Through the study of the internal pressure pulsation of a high-speed hydraulic turbine,it is found that the main frequency of the pressure pulsation of each component is about an integer multiple of the rotation frequency and the blade frequency,indicating that the internal pressure pulsation of the hydraulic turbine mainly comes from the dynamic and static interference and the rotation frequency.Partial operating conditions have a certain impact on the pressure pulsation of high-speed hydraulic turbines.The volute and runner are not greatly affected by changes in operating conditions,and the main frequency amplitude of the draft tube is greatly affected by changes in operating conditions.The research results of this paper provide a reference for improving the energy recovery efficiency and operation stability of hydraulic turbines in the high-speed field,and have certain significance for the research and application of hydraulic turbines in the high-speed field.