Research On Numerical Simulation Of Design Method And Loading Capacity Of Continuous Miner Star Wheel Mechanism

Continuous miner is a comprehensive mechanized miner.It is widely used in room and pillar coal mining and roadway driving in China.The star wheel mechanism is important components of continuous miner equipment.Its task is collecting and loading rock broken by the cutting mechanism on the conveying mechanism.The star wheel loading mechanism of continuous miner was the research object of this article.The discrete element simulation technology was used to realize the reconstruction of the star wheel loading coal and rock model.The discrete element simulation technology was also used to realize the simulation of the rock loading step.From the star wheel loading capacity theory,Gauss fitting method design,star wheel arm-coal interaction mechanism,star wheel loading mechanism loading performance analysis,star wheel full load starting torque prediction,and other aspects.The material fluidity mechanism and kinematic characteristics during coal loading were studied.The loading efficiency of the star wheel loading mechanism has been improved.Energy consumption has been reduced.The design cycle has been shortened.Firstly,the Gauss fitting method was applied to the design of the arm shape of the star wheel.A seven-arm loading star wheel was designed.The coal returning rate,rake coal torque,and minimum loading power indicators were proposed.A exhaustive assessment method for the loading capacity performance of the star wheel loading mechanism was also proposed.The influence of the number of arms and arm profile of the star wheel on the loading mass,the mass of coal returning,and rake coal torque were analyzed.With the help of EDEM software,the coal and rock loading model of the star wheel loading mechanism of the continuous miner with a simulated structure was reconstructed.The simulation structure includes coal wall,ground,feeder star wheel,coal and rock piles,etc.The coal returning state of the seven-arm loading star wheel was reappeared.The proposed evaluation methods of loading capacity indexes were used to compare the established seven-arm loading star wheel with EML340continuous miner with three-arm loading star wheel at the speed of 30 r/min and50 r/min.It has been found that the designed seven-arm 30 r/min loading star wheel has significantly increased loading efficiency than the EML340continuous miner with a three-arm 50 r/min loading star wheel.The average minimum loading power of the motors loaded with coal drives has been reduced by 34%.Secondly,a multi-condition feeder star wheel loading model was established.The interaction mechanism star wheel arm-coal was analyzed.According to the distribution pattern of the coal falling on the feeder.The loading of coal by the star wheel of the continuous miner was divided into four working conditions.A simulation model under coal loading with a static feeder was established.The change of the profile of the pile and the flow state of coal in the process of rake coal were analyzed.It has been found that in the process of continuous raking coal of the star wheel arm,the contour of the coal pile has been retracted away from the chute,resulting in a gradual decrease in the mass of coal raked by the star wheel.The shape of the profile gap of the coal pile was symmetrical with the centerline of the star wheel shaft.The maximum range of the star wheel arm to rake coal was approximately its diameter.The diameter mainly has determined the coal mass of the star wheel rake coal.The coal particles have slid along the slip line of the pile,thereby reducing the adhesion between the coal particles.If the coal particles were captured by the next adjacent star wheel arm at this time,it would indicate the fluidity effect of the coal in the active layer of the coal pile.Finally,a numerical simulation study on the loading performance and kinematic characteristics of the star wheel loading mechanism was carried out.The parameter matching analysis of the star wheel mechanism was also carried out.The influence law of feeder star wheel parameters on loading performance was given.The loading characteristics,load characteristics,and coal returning characteristics were analyzed.The full load starting torque was predicted.It has been found that loading efficiency has fluctuated.The number of star wheel arm Z and the star wheel speed n have affected the loading mass flow rate period T.The more the number of star wheel arm Z,the smaller the loading mass flow rate period T.The load peak has appeared at the position where the star wheel arm has been inserted into the pile,single-star wheel arm is the moment when the coal has been loaded and the entire star wheel arm has been annihilated in the coal pile.The farther away from the center of the star wheel,the greater the coal returning mass,the greater the speed of coal and rock movement and the direction of velocity perpendicular to the star wheel arm.The coal loading condition of shovel movement has been selected as a variable parameter.The number of star wheel arm Z,the height of the star wheel arm h,the depth S of the shovel inserted into the coal pile,and the higher the traveling speed V_X,the higher the loading efficiency and the coal returning efficiency.Knife-shaped star wheel has less loading mass,less coal returning mass,and higher energy consumption.14°shovel inclination angleβhas higher loading efficiency and lower energy consumption.The greater the number of star wheel arm Z,the height of the star wheel arm h,and the traveling speed V_X,the greater the energy consumption.The rock rejection rate is related to the feeder inclination angleβand the number of star wheel arm Z.Energy consumption is related to the depth S of the shovel inserted into the coal pile and the number of star wheel arm Z.When the pile height H is 1.5 m and the feeder inclination angleβis 14°,the peak torque is 25510 N·m.There is a large starting torque.This paper studies the star wheel loading capacity theory and Gauss fitting method of the star wheel loading mechanism of the continuous miner.A multi-condition feeder star wheel loading model is established.The theory of the arm-coal interaction is established.A numerical simulation study on the loading performance and kinematic characteristics of the star wheel loading mechanism is carried out.It is important to the structural design of the star wheel,the matching study of the loading and transportation mechanism,the continuous miner’s safe and normal operation.It is also important to the product display.