基于离散单元法的不同含水率土壤在转鼓中的流动行为研究OA北大核心CSTPCD

The remediation of POPs-contaminated soil by mechanochemical method has a promising prospect,but it is difficult to optimize the process parameters,because the particle movement information in the ball mill tank is hard to be obtained by experiment.Considering that the flow state of soil particles in the ball-milling tank is similar to that in the drum,this paper uses discrete element method(DEM)to study the flow behavior of soil with different moisture contents in the drum.In order to simulate the caking characteristics of soil,this paper uses Surface Cohesive Force model based on JKR theory to establish the cohesive force model of soil particles.The collapse period and centroid angle of the particles during the rotary drum test were used as indexes to verify the rationality of the simulation parameters.According to the results of the experiment and simulation,with the increase of soil moisture content,the collapse period of soil and the volume of single collapse block increase.The moisture content of soil is characterized by the polar component of surface energy γp in the simulation process.γp increases with the increase of moisture content,so that the agglomeration phenomenon under the action of cohesion becomes more obvious.In addition,the rolling friction coefficient of soil particles significantly affects the overall stratification effect of soil in the drum.Since spherical particles are used to replace soil aggregates,the selection of friction coefficient should not be limited to the range of friction coefficient of SiO2 materials,so as to ensure the consistency of simulation and experiment results.