Study On Dynamic Characteristics Of Wet Coal Mining Load Of Bucket Wheel Stacker And Reclaimer Based On Discrete Element Method

Bucket wheel stacker reclaimer is a type of mechanical equipment widely used in large open pit storage yards,large-scale port wharf,large-scale warehouse and other bulk material transportation plants.Due to the complex load characteristics of bucket wheel stacker reclaimer in the process of mining wet coal,the load of motor or drive mechanism will increase or even overload,and in serious cases,the motor may be damaged or the drive mechanism may fail.Key issues a load dynamic characteristic Therefore,herein mining wet coal for the bucket wheel reclaimer,establishing discrete element method bucket wheel reclaimer dynamic simulation model of a wet coal mining,mining studied the variation of resistance over time,and reasonably optimizes the working condition of wet coal mining.The details are as follows:1.The study on the characterization method of wet coal particles based on discrete element method is carried out.According to the actual condition of coal particles,the relevant parameters(particle size,water content,etc.)of coal particles are measured.And four typical shapes of wet coal particle models were established.By using the cylinder stacking test and taking the stacking Angle as the index,the characterization relation of water content of non-spherical wet coal particles based on surface energy was established through the simulation and the regression analysis of experimental results.The results showed that: The difference between the experimental and simulation mining resistance values is less than 2%,which indicates the accuracy of the dynamic simulation model for wet coal mining.2.The dynamic simulation model of wet coal mining is established and verified by experiments.Firstly,according to the actual bucket turbine mechanism,a simplified scale model was established.In order to ensure the accuracy of simplified modeling,the mass and stiffness distribution of the mechanism were consistent with the original structure.Then,according to the coupling relationship between the particles and the bucket turbine,the dynamic simulation model of wet coal mining in the bucket turbine is established and the corresponding dynamic simulation research is carried out.Finally,the model is verified by mining experiments with different water content.The results showed that: The difference between the experimental and simulation mining resistance values is less than 2%,which indicates the accuracy of the dynamic simulation model for wet coal mining.3.The paper studies the variation of the resistance of bucket wheel stacker reclaimer with the parameters of wet coal mining.Analysis of the bucket wheel during the wet coal mining impact,size,shape,moisture content and the speed of the digging resistance simulation method using single factor.The results showed that:(1)The smaller the particles,the greater the specific surface area and cohesion,the worse the fluidity,the greater the hindrance to the mining process,the greater the mining resistance;(2)When the particle size is in the same phase,the change of adhesion force between particles with different shapes is small,resulting in no obvious difference in the change of mining resistance when excavating particles with different shapes.(3)When the humidity is small,the moisture content increases,and the drag of particle friction on the bucket increases.On the contrary,the drag of particle on the bucket decreases,which leads to the trend that the excavation resistance increases first and then decreases with the increase of moisture content.(4)The greater the rotational speed is,the greater the impact force on the bucket when it contacts with wet coal is.Therefore,the obstacle effect on the bucket is enhanced,and the excavation resistance is also greater.4.Reasonable optimization of coal mining conditions was wet.Through the response surface method,taking the mining resistance as the index,the factor variance analysis of the mining parameters is carried out,and the significance of a parameter to the mining resistance is obtained.The optimization design of bucket wheel speed is carried out with the aim of low digging resistance and high productivity.The results showed that:(1)Among the three factors,the rotational speed has the greatest influence on the mining resistance and the smallest influence on the moisture content;(2)When the moisture content is small,the speed of small particle wet coal is set at about 10r/min,while the speed of large particle wet coal is set at about 7r/min;(3)When the moisture content is large,the rotational speed of small particle wet coal is set at about 10r/min,and when large particle wet coal is mined,the rotational speed is set at 7r/min.