Impeller Design Of Slurry Pump And Wear Test Research

Slurry pump is the main equipment for conveying solid materials,which is widely used in mining,electric power,marine engineering and other important industries.The common structure of the slurry pump is centrifugal pump or mixed pump.Because the solid particles in the conveying medium act on the inner wall of the pump in different forms,parts of the flow passage are prone to wear,reducing the service life.It is still a problem to be solved in the field of pumps to reduce the wear and prolong the service life of slurry pumps.In this paper,a slurry pump is taken as the research object,the mixture of quartz sand and water is used as the transport medium,and the Euler-Euler particle model in CFX is used to simulate the solid-liquid two-phase flow in the slurry pump,to analyze the reasons for the reduction of the characteristics of the slurry pump;the solid volume fraction and slip speed are used as a reference,qualitative analysis of the causes of slurry pump impeller wear,combined with mathematical statistics method to optimize the slurry pump impeller,the main research work and conclusions are as follows:(1)This paper introduces the research status of slurry pump at home and abroad,and compares the development process of slurry pump at home and abroad comprehensively;It introduces the research status of slurry pump wear mechanism at home and abroad,and summarizes several main wear models and wear formulas;At last,it introduces the test research status of slurry pump at home and abroad,and summarizes several commonly used test methods.(2)It introduces the current methods used to simulate solid-liquid two-phase flow,and compares the application scope,advantages and disadvantages of each numerical method;It also introduces several commonly used optimization methods,and expounds the relevant theories and application scope of each optimization method.(3)The Euler-Euler particle model is used to simulate the solid-liquid two-phase flow in the slurry pump.The flow in the impeller of the slurry pump under different flow conditions,different solid volume fraction and different particle size is analyzed,and the distribution of solid volume fraction and solid slip velocity in the impeller is compared and analyzed.The results show that: under the condition of small flow,the suction surface of the blade is close to the inlet and the area with high solid volume fraction appears on the inner wall of the impeller inlet;the sliding speed of the pressure surface of the blade is higher than that of the suction surface as a whole;under the condition of small flow and design flow,the sliding speed of the front and the tail of the working surface of the blade is higher than that of the middle;the distribution of the sliding speed on the pressure surface of the blade is not uniform,and the blade outlet is not uniform.The slip velocity at the interface of impeller and volute is the highest near the shroud and hub,and when the flow increases to the design flow,the high-speed area transfers to the middle of the interface;the increase of solid volume fraction and particle size will lead to the decrease of pump head and efficiency;The increase of solid volume fraction will lead to the increase of blade outlet slip velocity.The increase of particle size leads to the increase of blade outlet slip velocity and solid volume fraction.(4)The response surface method is used to study the four key design parameters of impeller: blade number,impeller diameter,blade outlet width and wrap angle.The test consists of full factor test and response surface test.The results show that the significant order of influencing head is: impeller diameter > blade number > blade outlet width > wrap angle;the significant order of efficiency is: impeller diameter > wrap angle > blade outlet width > the quadratic term of blade number.By solving the regression equations of head and efficiency,a group of optimization solutions and the prediction values of head and efficiency are obtained.The results show that the deviation between the calculated value of head and efficiency and the predicted value is within 5%,and the fitting effect of regression model is good.By comparing the results of solid-liquid two-phase flow between new pump impeller and original pump impeller,it is found that the solid-phase slip velocity at the outlet of new pump blade and the interface between impeller and volute decreases obviously,the distribution of solid-phase slip velocity on the pressure surface of blade is more uniform,and the solidphase volume fraction on the inner wall of impeller inlet decreases.(5)The original pump and new pump were manufactured,and the wear tests of the two slurry pumps were carried out at the same time.In order to speed up the wear test,the particle size of solid particle quartz sand was increased from 100 mesh to 40 mesh,the proportion of slurry was increased from 1.02g/ml to 1.7g/ml,and the speed of pump was increased by 210 r / min;the solid particle brown corundum was added in the later stage of the test,and the wear test was run for 103.5h,marked by the obvious drop of the outlet pressure of the original pump.The test results show that the pressure surface of the impeller blade of the original pump is seriously worn,and the interface between the blade outlet and hub is worn through.The circular arc design of the original pump blade outlet is more worn than the linear design of the new pump impeller outlet;the wear of the suction surface of the original pump blade near the inlet is more serious than the new pump;the interface between the front edge of the original pump blade and hub is worn through.Compared with the test results of original pump,new pump effectively reduces the wear.It prolongs the service life and achieves the expected design goal.