基于离散单元法的颗粒物料休止角仿真研究

发布时间：2018-05-02 10:35

本文选题：物料状态 + EDEM　；参考：《湖南大学》2016年硕士论文

【摘要】：颗粒物料在自然界和工程应用领域中极为普遍,休止角(repose angle)是颗粒物料的一种重要物理属性,是表征转筒类过程装备内物料状态的重要特征量。国内外学者对休止角进行了很多实验研究,但在目前的研究成果中,实验对象大部分为球形颗粒,而实际工业生产中的物料形状主要为不规则颗粒,球形颗粒的运动规律是否能够反映非球形颗粒的运动还有待于验证。此外,实验转筒的尺寸普遍偏小,与实际生产所应用的转筒尺寸有较大差别,是否能将小转筒所得到结果上推到工业尺度回转筒装备中还需要进一步研究。针对以上问题,本文根据实验室回转筒设备以及圆柱体颗粒物料的实际尺寸,对不同转速下(2.87rpm-17.23rpm)的颗粒物料运动过程进行DEM建模和仿真,在EDEMTM环境下完成了各模块的参数设定。搭建了相应的回转筒实验平台,来模拟转筒型过程装备中圆柱体颗粒物料的运动状态,通过图像采集装置获得物料运动的图像信息。给出了基于图像处理技术的颗粒物料动态休止角的检测算法,并基于以上算法对物料状态图像进行检测,获得不同操作参数下的颗粒物料休止角仿真实验曲线以及物理实验曲线。通过对物料状态图像、休止角动态变化曲线的对比,验证了DEM仿真结果的正确性。基于所建立的精确DEM模型,对工业尺度回转筒内的颗粒系统进行了不同实验条件下的仿真实验。研究发现,转筒直径不变时,休止角随着转速的增加,由30.27±1.50度增长34.03±0.32度,有明显的上升趋势；转速不变时,随着转筒直径的增加休止角由37.23±2.49度下降到28.64±0.49度,有明显的下降趋势。该结论与其他人员在小转筒内所得结论一致,证明在小转筒内所得的休止角规律可以上推至一定范围内的工业尺度转筒中。
[Abstract]:Granular materials are very common in nature and engineering applications. Repose angle is an important physical property of granular materials and an important characteristic quantity to characterize the material state in rotary process equipment. Scholars at home and abroad have done a lot of experimental research on the angle of repose, but in the current research results, most of the experimental objects are spherical particles, while the material shape in actual industrial production is mainly irregular particles. Whether the movement law of spherical particles can reflect the movement of non-spherical particles remains to be verified. In addition, the size of the experimental rotary drum is generally small, which is different from that of the actual production. Whether the results of the small rotary drum can be pushed to the industrial scale rotary equipment should be further studied. In order to solve the above problems, according to the actual size of the rotary cylinder equipment and the cylinder particle material, this paper models and simulates the particle material movement process of 2.87rpm-17.23rpm at different rotational speeds by DEM, and completes the parameter setting of each module under the EDEMTM environment. A rotating cylinder experimental platform was built to simulate the motion state of the cylindrical particle material in the rotary process equipment, and the image information of the material movement was obtained by the image acquisition device. An algorithm for detecting dynamic angle of repose of granular material based on image processing technology is presented, and the image of material status is detected based on the above algorithm. The simulated experimental curves and physical experimental curves of the angle of repose of granular materials under different operating parameters were obtained. The correctness of DEM simulation results is verified by comparing the dynamic curve of material state image and angle of repose. Based on the established precise DEM model, the simulation experiments of the particle system in the industrial scale rotary cylinder are carried out under different experimental conditions. It is found that the angle of repose increases obviously from 30.27 卤1.50 degrees to 34.03 卤0.32 degrees with the increase of rotating speed, and decreases from 37.23 卤2.49 degrees to 28.64 卤0.49 degrees with the increase of rotating speed. The conclusion is in agreement with the conclusion obtained by other people in the small drum. It is proved that the law of the angle of repose obtained in the small drum can be pushed up to a certain extent in the industrial scale cylinder.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB383;TP391.41

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