The Research Of Flow-induced Noise Of Underwater Pump And Optimal Design

In recent years,noise problems have exerted increasingly serious impacts on modern life.As an important general machinery in the field of energy conversion,the noise pumps generate during operation has become an significant factor in environmental noise.Therefore,it is very necessary to study the noise problem in the operation of the pump.This paper analyzed the flow law of an underwater pump,discussing the main sound source in the underwater pump.The direct boundary element method(DBEM)model was used to simulate the hydrodynamic noise induced by volute surface dipole as well as the blade rotating dipole in the pump.Analyses of the characteristics of sound field were conducted according to calculation results.In order to reduce the hydrodynamic noise,the optimal design of the impeller was carried out by using the method of response surface method.1.The research background of this topic,research significance as well as research methods of the flow noise were introduced.The current situation and development of noise research and the research results of hydraulic and acoustic performance optimization in turbomachinery at home and abroad were summarized.2.The hydraulic design methods of pump were introduced in this paper.The design of the underwater pump was carried out according to the actual operation requirements,and the three-dimensional model of the pump was constructed by ProE.3.Dividing the grid of 3D calculation model by IC EM,The irrelevant effect of different grid number on simulation was verified.The external characteristic experiment was carried out,and the error between the numerical calculation and the test result were compared.The steady and unsteady calculation of the underwater pump were simulated by ANSYS CFX,and the velocity field and pressure field were analyzed.Through unsteady calculation,the pressure pulsation in flow field was obtained by the 12 monitor points of pressure pulsation set in the model pump.The frequency characteristics of pressure pulsation were obtained by fast Fourier transform,which revealed the law of the pressure pulsation of the internal flow field.4.Introduce the basic knowledge of acoustics and the calculating method.The direct boundary element method(DBEM)model was used to simulate the hydrodynamic noise in the pump induced by volute surface dipole as well as the blade rotating dipole.According to calculation results,the sound pressure frequency curves of acoustic field monitor was obtained.5.The hydraulic efficiency and the flow noise were taken as the optimization objective function.The influence of main parameters on flow noise was analyzed by single factor experiment,where the impeller parameters with significant influence on flow noise were selected as optimum design parameters.The Box-Behnken design method was used to design the selected sensitive parameters,and the regression models of hydraulic efficiency and flow noise were obtained by response surface method.Through simultaneous regression equations,the optimization model with the minimum flow noise and no reduction of hydraulic efficiency was obtained.The sound pressure level and hydraulic efficiency of the optimization model were compared with that of original model,which showed the feasibility of the response surface method to optimize the acoustic performance of the underwater pump.