Fluids Fields Characteristics And Structure Optimization Of Accelerator Of Decanter Centrifuge

The feed accelerator is a key component of the horizontal screw centrifuge,and the main function is to transport the material in the feed pipe to the centrifuge drum.However,when the LW350 decanter centrifuge is used to process copper slurry materials,the inner wall of the accelerating disk is severely worn due to the impact of solid particles,which would result in structural failure.Consequently,this paper studied the fluid motion state and flow characteristics in the accelerator,analyzed the causes of the accelerator wear,and an optimized design of the acceleration disk was proposed.The high-frequency image experiment system for accelerator was designed and built,which mainly included the accelerator experiment host,high-frequency timing synchronization system and flow field fluorescent tracer system.The experimental platform has a translucent design.The designed high-frequency timing synchronization system consists of two programmable logic controllers and one synchronizer,which can achieve deviation within 50 ns.In order to overcome limitation of the traditional PIV laser on the rotating equipment,a set of PIV system for rotating equipment was developed,and special fluorescent particles was synthesized as tracer particles,which could help study quantitatively the flow field characteristics in the accelerator.The accelerator high-frequency image experiment system was used to study the variation of fluid trajectory and velocity vector in the accelerator under different operating conditions.The results show that there were two ways of outflow of fluid:radially flowing out and accelerated outflow,the radically flowing out ratio will decrease as the flow rate increases or the speed decreases.The steering angle of the fluid that was accelerated to flow out became larger as the rotational speed increased,and became smaller as the flow rate increased.When the speed increased from 990r/min to 2310 r/min,the steering angle is increased from 52.66°to 85.35°.When the flow rate increased from 9m~3/h to 18 m~3/h,the steering angle is reduced from 75.18°to45.34°.According to the analysis of flow field characteristics,the violent collision of the accelerating fluid on the accelerator is the main cause of wear.The collision mainly occurs in the concave outer region,while the inner region and the convex region not only have no gain for acceleration,but instead block the radial outflow of fluid.According to the analysis of flow field characteristics,the accelerator optimization strategy was determined.The free motion equation of emitted rotationally particle was used as the profile drive of the flow channel,and then the accelerator structure was designed and optimized.The accelerator multiphase flow numerical model was established and validated with deviation of 13%.The vector shows that the accelerating area of the optimized accelerator is significantly higher than the original structure.The area with a wear factor greater than 700 is reduced by 51.7%,and the efficiency is only12.1%lower than that of the original accelerator.