| Due to the increasing depletion of terrestrial mineral resources,the development of marine energy has become an important strategic goal for countries around the world.As one of the key equipment of deep sea mining conveying system,the hydraulic performance of the slurry pump is the standard for examining the work of the pump,and easy wear is the main problem of the pump.The aim of this project is to combine theoretical analysis and CFDDEM numerical simulation method to numerically simulate the liquid-solid two-phase flow field inside the slurry pump,to study the liquid-solid two-phase flow and guide vane wear characteristics inside the slurry pump,and to solve the problems of the slurry pump conveying technology.The key research contents and conclusions of this thesis are as follows:Firstly,based on the fluid-solid coupling theory and Newton’s law of motion,the motion and force characteristics of particles in different conveying environments are studied,and the lift and traction models for studying non-spherical particles in this thesis are selected.By analyzing the actual operation of the slurry pump conveying system,a suitable built-in calculation model is used to determine the parameters of liquid and solid phases.Next,the design parameters of the slurry pump are determined based on the working environment of the slurry pump,and the slurry pump is modeled in three dimensions.The influence of flow rate on pump head,efficiency and power is analyzed,and the results are compared with experimental results of others to determine the reliability of the mine slurry pump model.Numerical simulation is carried out for the hydraulic performance of the slurry pump,and the best vane spiral angle of the slurry pump is determined by comparing the flow field conditions and hydraulic performance indexes of five different vane spiral angles of the slurry pump.The results show that when the spiral angle is 30°,the pump decoupling phenomenon is reduced,the head and efficiency reach the maximum value respectively,and the power consumed by the pump is lower.Then,the coupled CFD-DEM method is used to numerically simulate the liquid-solid two-phase flow inside the slurry pump to study the effects of different operating conditions(such as speed,flow rate,particle size and particle shape)on the internal pressure,velocity and particle concentration of the slurry pump.It was found that the vortex and secondary flow phenomena were generated inside the pump,which would increase the hydraulic loss of the pump and reduce the operating efficiency of the pump.The results show that the vortex range in the impeller area is the largest at high speed,low flow rate,small particle size and spherical particle conditions;the secondary flow intensity in the inlet area of the pressure surface of the guide vane is the highest at high speed,low flow rate,large particle size and cylindrical particle conditions;the vortex range and secondary flow intensity in the suction surface of the guide vane are the largest at low speed,high flow rate,large particle size and spherical particle conditions.Finally,based on the discrete phase model,numerical simulations of the force state of particle motion in the slurry pump are conducted to reveal the number of collisions between solid phases,solid phases and the walls of the overflow components and the wear characteristics under different working conditions of speed,flow rate,particle size and particle shape.The results show that the number of collisions between solid phases is the highest at high speed,low flow rate,small particle size and cylindrical particles;the number of collisions between solid phases and guide vane is the highest at high speed,low flow rate,small particle size and trigonal particles;the wear of guide vane pressure surface is the most serious at high speed,high flow rate,large particle size and trigonal particles,and the wear locations are mainly concentrated in The wear is mainly concentrated in the middle steering area. |
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