Study On The Collision-abrasion Mechanism Of Solid-Liquid Two-phase Flow In Variable Curvature Pipe

Pump is the power core of fluid transportation.While transporting solid-liquid flows,impact between particles and flow-passage parts will cause severe erosive damage and low efficiency.But for the complex structure of impeller,the study on two phase flow in it is difficult.In order to reveal the wear mechanism of large-particle solid-liquid flow in the impeller,the impeller passage was simplified to the variable curvature flow passage.The pipe line of the variable curvature flow channel adopted the impeller blade profile.The high-speed photographic technique,erosion test,and CFD-DEM coupled calculation method were used to study the solid-liquid mixture flow in the variable-curvature elbow and reveal its wear mechanism.The main research contents are as follows:(1)The development of particle-liquid flow and wear mechanism in flow-passage parts were summed.The development of simplified research on internal flow of rotating machinery was introduced.Rotation and blade profile are two key factors that affect the internal flow of impeller.The basic theory of discrete element method and its development were introduced.(2)Experimental platform including a high speed photography and variable curvature elbow was designed.The visualization experiment of particle motion in pipe was carried out.The Matlab software was used to analyze the image data.The influence of particle density,wall material,incident position and fluid velocity on the particle motion trajectory and velocity were studied.(3)An experiment platform for wear test was designed and built.And the wear test was carried out.The change of wall wear with the mass concentration of the mixture was analyzed.The surface wear morphology and cause of wear sheet are analyzed explicitly.(4)The continuous phase control equation and the discrete phase particle motion control equation in the CFD-DEM coupling model were introduced,and the numerical simulation results were analyzed.The change of the velocity of the particles in the mixture and the effect of fluid flow on the particle motion were explained in the elbow.