Study On Considering The Influence Of Electrstatic Charge On Cross Section Particle Flow In Vertical Pipe

The transportation of particulate matter is one of the important links in industrial production.Pipeline transportation is the main transportation method of particulate matter.During the transportation of the particles in the pipeline,the particles collisions and rubbing due to the contact with the wall of the transportation pipeline and other particles,which causes the particles to carry some charges.So that particles are acted upon by electrostatic forces during the movement,which further affects the particle's speed and movement,further to affect the efficiency of pipeline transportation.Although people have noticed that the electrostatic phenomenon in the pipeline particle flow,and have invented the technology to monitor the pipeline flow rate by the change in electrostatic charges,there is few research to investigate the effect of the pipeline flow rate by considering the generation and accumulation of charges carried by the particles.Therefore,this thesis focuses on the generation and accumulation of charges carried by particles due to collisions between the particles and particles with the pipe wall,to study the pipeline flow rate.The main work and results are as follows.First,in this paper,the discrete element software EDEM combined with the collision charging model of particles due to the collisions between the particles,and particles with the wall,is used to simulate the particle flow in a vertical pipeline.It is found that the larger the particle size and the greater the collision speed is,the greater the ball or plate charge is.When the particle diameter ratio of the two particles is 0.6,the charges carried by the particle reaches the maximum value,which verifies our codes implanted in the EDEM,and it is credible to simulate the pipe flow by considering the charges carried by particles.Then,based on the above collision charge model and EDEM softwarethe,particle flow rates and the charges carried by particles in vertical pipe are studied under the given pipe radius,pipe length and particle size distribution.The results indicate that the smaller the pipe diameter is,the more distinguish the effect of the charges on the flow rates is;the longer the pipe length is,the more distinguish the effect of the charges on the flow rates is;the larger the particle size distribution range is,the more distinguish the effect of the charges on the flow rates is;the larger the loading rate is,the more distinguish the effect of the charges on the flow rates is;the more different the particle and pipe wall material properties is,the more distinguish the effect of the charges on the flow rates is.When the pipe diameter is smaller and the pipe length is longer,the charges considered to simulate the particle flow to make the flow rate increase by 25%.When the pipe diameter is smaller than 16 mm and the pipe length is less than 80 mm,the charging effect is less than 7%.Finally,an experiment is carried out to measure the sand particle rate in a vertical pipe under different pipe radius,pipe length and particle size distribution.And compared with the numerical results.It is founded that the influence of pipe length,pipe diameter and particle size distribution on pipe flow is consistent with the numerical results but the numerical simulation results are larger than the experimental results.And numerical simulation results under considering charging are closer to experimental results.but the maximum difference under considering charge is 14% from experimental results,and the maximum difference under without considering charge from experimental results is 39%.