Research on discrete element method simulation of crushing force for double-toothed roller crusher

Based on the theory of discrete element method,the particle contact model,the particle contact search algorithm and the iteration time step algorithm in the analysis process are improved,and the force of the tooth roll in the crushing process is analyzed to ensure that the strength and life requirements are met.The improved discrete element method is used to simulate the crushing process of the first rough crushing section of the double-tooth roller crusher.Firstly,the discrete element method is used to simulate the crushing process of coal particles by the double-tooth roller crusher,and the crushing force of the double-tooth roller crusher is obtained.The results are compared with the solution calculated by the traditional empirical formula.The simulation results under different parameters were analyzed,and the influence of the speed and particle diameter of the tooth roll on the crushing force was studied.Then,combined with Hertz-Mindlin non-sliding contact model and Hertz-Mindlin bonding contact model,the particle contact model is simplified to vibration motion model and the calculation formulas of each component force are derived respectively.On the basis of EDEM software,the second development was carried out,and the coal particle contact model combined with the two models was constructed by API plug-in.Before entering the crushing chamber,coal particles are transformed into compact aggregates of several small particles,and bonding contacts are exerted between the small particles.When the external force between any two small particles is less than the binding constraint force,the relative displacement between the small particles is neglected,so that the particle set still moves in a whole shape.When the external force between two small particles is greater than the binding force,the binding constraint between the two small particles is cancelled to separate the small particles from the aggregate.The contact model of coal particles established by this method can effectively simulate the complete crushing process of coal particles,and save computing time and resources.Finally,through comparative analysis,the optimal value of contact retrieval mesh size used in numerical simulation of double tooth roll crusher is obtained.Taking YLWP+S1000-1500WX double-toothed roller crusher newly designed and manufactured as an example,the influence law is studied.The crushing process of coal-fired particles is simulated by the above-mentioned theoretical method,and the force change curve of crushing teeth in the crushing process is extracted.The maximum crushing force load and average crushing force load of single row crushing teeth on the first rough crushing roll in the process of crushing normal coal particle are obtained,and the influence law of particle diameter and rotational speed of gear roll on the force of crushing teeth is obtained.It provides a reference for the design of crusher and the prediction of crushing capacity.