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| 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 |
| Study on the flow behavior of soil with different moisture content in drum based on discrete element method |
| 投稿时间：2023-01-13 修订日期：2023-02-14 |
| DOI： |
| 中文关键词: 离散单元法 土壤 结块 转鼓 表面能 |
| 英文关键词:DEM soil agglomeration rotary drum surface energy |
| 基金项目:国家自然科学基金(22078283)；国家重点研发计划(2019YFC1805605)资助项目；国家市场监督管理总局科研计划项目(2019MK154) |
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| 中文摘要: |
| 机械化学法修复POPs污染土壤应用内前景良好，但由于无法通过实验手段获取球磨罐内颗粒运动信息，难以对工艺参数进行优化。考虑到土壤颗粒在球磨罐中的流动状态与在转鼓中十分相似，本文采用离散单元法（DEM）研究不同含水率土壤在转鼓中的流动行为。为了模拟土壤的结块特性，本文采用基于JKR理论的Surface Cohesive Force模型建立土壤粘聚力模型，并以转鼓试验过程颗粒的坍塌周期和质心角为指标验证了仿真参数的合理性。根据试验与仿真的结果可得，土壤的含水率越高，转鼓中土体坍塌周期和单次坍塌块体体积越大；土壤含水率在仿真过程中以表面能极性分量为表征，含水率越高，表面能极性分量越大，土壤内聚力作用下的结块现象越明显。此外，在仿真过程中，土壤的滚动摩擦系数显著影响转鼓内土壤颗粒整体的分层效果。由于本文使用球形颗粒代替土壤团聚体，摩擦系数的选取不应限于SiO2材料的摩擦系数取值范围，才能保证仿真与试验结果的一致性。 |
| 英文摘要: |
| 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 content 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 rotary drum test were used as indexes to verify the rationality of the simulation parameters. According to the results of 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. |
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