Hydraulic And Acoustic Performance Analysis And Multi-objective Optimization Of Low Specific Speed Centrifugal Pump

Noise pollution is the second major factor in environmental pollution.Designing quiet industrial products and controlling noise emissions from existing equipment has become an important development trend.As a fluid delivery device,centrifugal pumps are widely used in multiple fields of industrial production.However,its working process is accompanied by noise generation,which not only harms the equipment itself but also the external environment.The hydraulic performance and acoustic performance of centrifugal pumps are both interrelated and contradictory in the process of hydraulic structure design.Currently,improving pump efficiency and reducing pump noise is an important research focus.This paper mainly studies the influence of the trapezoidal cutting of the blade outlet and the multi-objective optimization design of the volute on the acoustic and hydraulic performance of the centrifugal pump,we hope to optimize the both acoustic and hydraulic performance of centrifugal pumps.Firstly,a full three-dimensional unsteady numerical calculation of the flow field of a centrifugal pump is worked with RNG k-εturbulence model.Secondly,the calculation of the internal field noise through the boundary element method,and the structural finite element coupled acoustic boundary element method is used to calculate the flow induced noise in the external field.The main contents of this paper are as follows:1.The influence of trapezoidal cutting of blade outlet on the induced noise of centrifugal pump volute.Taking the centrifugal pump with a specific speed of 66 as the object,by defining the cutting width coefficient δ And radial height coefficient γ,Nine cutting schemes are designed.The hydraulic characteristics and noise radiation characteristics of centrifugal pumps under different cutting schemes are analyzed,and the accuracy of numerical calculation is verified by test methods.The research shows that the rotor-stator interaction was the main cause of the flow-induced noise of the volute of the centrifugal pump.The reasonable trapezoidal cutting can stabilize the hydraulic performance of the pump and effectively reduce the rotor-stator interaction intensity and the flow-induced noise level of the volute.The sound pressure level at the inlet and outlet monitoring points at the blade frequency reduced by 13% and 7.5%respectively,and the sound pressure level at the field noise monitoring points decreased by 2.4%.2.Multi-objective optimization design in a centrifugal pump volute based on RBF neural network and genetic algorithm.An optimization design method of a centrifugal pump volute based on radial basis function(RBF)neural network and genetic algorithm(GA)is proposed to solve this problem.The objective of this optimization is to set the efficiency and total sound pressure level of the centrifugal pump.The optimization variables mainly include the diameter of the base circle,the installation angle of the volute tongue,the width of the base circle,and the volute diffuser height.The Latin hypercube sampling(LHS)is used to establish the sample space,the RBF neural network is used to build the agent model between the optimization variables and the optimization objectives,and the GA is used to carry out multi-objective optimization.For the Pareto solution set obtained,two extremal individuals and initial individuals are selected for comparative analysis of hydraulic performance and acoustic performance under different working conditions.The result shows that under the rated working condition,compared with the initial individual,the efficiency of the optimal individual of efficiency is increased by 3.79%,the peak value of pressure pulsation at the blade frequency is reduced by 4.4%,the internal noise is reduced by 1.4%,and the external noise is reduced by 0.6%;When the individual has the optimal sound pressure level,the efficiency is increased by 1.1%,the peak value of pressure pulsation at the blade frequency is reduced by 14%,the internal noise is reduced by 5.5%,and the external noise is reduced by 2.3%.It is proved that the optimization design method can improve the hydraulic performance and acoustic performance of centrifugal pumps at the same time and has specific feasibility.