Research On The Effect Of Coordinated Design Of Blade Wrap Angle And Blade Number Of Centrifugal Pump On Solid-liquid Two-phase

The centrifugal pump is a general machinery commonly used in the industrial and agricultural field.The parameter design of the impeller is a key point that affects performance.The parameter design of the blade wrap angle and the number of blades is particularly important to its performance.Changing the blade wrap angle or the number of blades for this research has made little research on the collaborative design of the blade wrap angle and the number of blades.In actual engineering,the conveying medium is generally multi-phase flow,so for centrifugal pumps operating under solid-liquid two-phase flow conditions,collaborative research is particularly important,so this article will explore the high specific speed centrifugal pump blade wrap angle and number of blades The two-parameter co-design method and its codesigned high specific speed centrifugal pump solid-liquid two-phase flow are studied in depth,which provides a reference for the subsequent study of the effect of blade parameters on the solid-liquid two-phase flow of the centrifugal pump.Based on the modern pump design theory and numerical simulation method,the paper determines the collaborative design scheme of the blade package Angle and blade number of the centrifugal pump with high specific speed,establishes the three-dimensional flow calculation model of the centrifugal pump with high specific speed,and numerically simulates the solid-liquid two-phase flow of the centrifugal pump under steady and unsteady conditions by using the fluid analysis software CFX.of high specific speed centrifugal pump under different particle concentration in the blade Angle and leaf number of the collaborative design efficiency,lift performance was analyzed,and the changes of the various research plan under a certain particle concentration distribution,particle velocity distribution of impeller,the impeller pressure after the particle volume fraction distribution rule and dimensionless particle velocity and particle volume fraction in the distribution of the specific location within the impeller.At the same time,monitoring points are set in the impeller runner and volute,and the changes of instantaneous pressure,instantaneous turbulent kinetic energy,pressure pulsation and radial force are discussed.The main research results are as follows:(1)Under clear water conditions,with the increase of the blade wrap angle,the efficiency of the centrifugal pump gradually increases,and the head increases first and then decreases.Under the conditions of solid-liquid two-phase flow,with the increase of the blade wrap angle,the efficiency of the centrifugal pump increases first and then decreases,and the head gradually decreases.In the case of sand,the change of the wrap angle has little effect on the optimal efficiency value.The increase of the wrap angle reduces the overall pressure in the impeller,but improves the particle volume distribution in the impeller,the pressure fluctuation in the volute,and the design flow rate.The radial force of the impeller and diaphragm,but it will increase the particle velocity,design flow rate and overall flow pulsation of the impeller in the impeller.(2)Under the conditions of clean water and solid-liquid two-phase flow,as the number of blades increases,the efficiency and head of the centrifugal pump increase.In the case of sand,the change in the number of blades has little effect on the optimal efficiency value.The increase in the number of blades increases the overall pressure in the impeller,reduces the solid velocity,and reduces the distribution of particle volume fraction,while reducing the overall centrifugal pump.Pressure pulsation.(3)In each collaborative design scheme of blade wrap angle and blade number,the optimal blade wrap angle value of the centrifugal pump under solid-liquid two-phase flow and clean water conditions gradually decreases with the increase of the blade number.Compared with the clear water condition,the two-phase flow conditions of solid-liquid flow have different optimal blade angle values for the efficiency of different blade number schemes,a narrower efficiency range,and a faster head fall rate.The effect of collaborative design on the efficiency of centrifugal pumps under solid-liquid two-phase flow is greater than that of clean water.Under the solid-liquid two-phase flow condition,the efficiency in the “Z=7 and φ=80°” scheme is optimal.(4)In the collaborative design schemes of blade wrap angle and number of blades,the larger solid phase velocity in the impeller appears at the leading edge of the blade,and extends to the blade working surface near the water outlet through the middle section of the flow channel,and the particles are mainly concentrated in The second half of the suction surface of the blade.Under different flow rates,appropriately increasing the blade wrap angle and the number of blades at the same time will improve the pressure,solid velocity and solid phase volume fraction distribution in the impeller,but when any of the blade wrap angle and the number of blades increases too much,The pressure,solid velocity and solid phase volume fraction distribution in the impeller will be worse,the pressure distribution in the “Z=7 and φ=100°” scheme is optimal,and the “Z=6 and φ=90°” scheme The particle velocity distribution is optimal,and the particle volume fraction distribution in the "Z=5 and φ=110°" scheme is optimal.(5)In the collaborative design schemes of blade wrap angle and blade number,the pressure changes in a gradient during the same period,and the turbulent kinetic energy is concentrated on the suction surface of the blade.Properly increasing the wrap angle and the number of blades at the same time can improve the instantaneous pressure,instantaneous turbulent kinetic energy of the impeller,the pressure pulsation and radial force of the centrifugal pump,but when both are increased too much,the instantaneous pressure of the impeller,instantaneous turbulent kinetic energy,centrifugal pump The pressure pulsation and radial force distribution will become worse.There are instantaneous turbulent kinetic energy in the “Z=6 and φ=90°” scheme,instantaneous pressure and pressure pulsation in the “Z=7 and φ=100°” schemes,The radial force is optimal.(6)In the collaborative design schemes of blade wrap angle and number of blades,under different particle concentration conditions,the wrap angle value of centrifugal pump efficiency,which is the most advantageous,decreases as the number of blades increases.As the particle concentration increases,the efficiency,head,and optimal blade wrap angle of each blade number scheme decrease.In the presence of clean water,particle concentration Cv = 1%,Cv = 2%,Cv = 3%,the optimal collaborative scheme with the goal of efficiency is "Z=7 and φ=100°","Z=7 and φ=100°","Z=7 and φ=80°","Z=7 and φ=70°".