| Centrifugal slurry pump is widely used in industries involving solid-liquid two-phase medium transportation,such as mining,metallurgy,electricity,environmental protection.The hard-solid particles in the medium have strong abrasion to the flow-components,which leads to low efficiency and short life-span of the pump.In this paper,to analyze the relationship between impeller blade profile,solid phase parameters and internal flow,wear characteristics,LC100/350 slurry pump was taken as an objection,limestone slurry was employed as medium,blade profile was controlled by logarithmic helix method,the discrete phase model(DPM)was used to numerical calculation.The flow and external characteristics of the pump were analyzed with different particle velocities,sizes and concentrations as well as four wrap angles of blade profiles,including 90°,100°,110°,120°.The results show that:1.The cylindrical blade designed by variable angle spiral method is beneficial to reduce the shaft power and improve the hydraulic efficiency of the pump on the whole,but it will lead to a small reduction of the water head.In general,with the increase of blade wrap angles,the wear on the impeller and the hydraulic efficiency of the pump will increases.Among the four blades,the one of the 100° wrap angle has the least wear intensity,whose blade angle changes with a linear way.2.Impeller wear intensity is mainly distributed in the hub.Therefore,the average wear intensity of the hub can characterize the wear characteristics of impeller.Because the impeller is symmetrical,the wear intensity is similar in each single flow passage.There is a positive correlation between wear strength and solid concentration,the higher the solid concentration is,the greater the wear strength is.The turbulent intensity distributions in the middle plane and the axis plane of the impeller passages with four blade profiles are similar and distribution rule is basically the same: the region of high turbulent intensity mainly concentrates on the position where the vortex and the detachment occur,that is,near the suction of the blade in the runner;with the increase of the blade wrap angle,the turbulent intensity in the impeller decreases gradually and the efficiency of the pump increases gradually.3.About influence of solid phase parameters on pump performance.The influence of inlet particle velocity: with the increase of flow rate,the wear intensity increase firstly and then decrease,and wear intensity is the largest and the efficiency is also the highest at rated condition,the blade wrap angle has little effect on the wear characteristics of impeller under small flow rate,but much more significant under large flow rate.The influence of particle size: with the increase of particle size,the average wear strength of impeller increases gradually.Under different particle size,the trend of wear characteristics with wrap angle is completely consistent.The influence of solid phase concentration: with the increase of solid phase concentration,the average wear strength of impeller increases gradually,and the trend of wear characteristics with wrap angle is completely consistent under different solid phase concentration conditions. |
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