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Investigation of discharge characteristics of rod-shaped particles in a hopper: Experimental and numerical studies using polygonal/polyhedral DEM
Advanced Powder Technology ( IF 5.2 ) Pub Date : 2020-09-18 , DOI: 10.1016/j.apt.2020.08.024
Jihoe Kwon , Dong-Woo Ryu

In this work, the discharge of numerous polygonal particles in a hopper was investigated numerically and experimentally. To this end, a polygonal/polyhedral DEM model is proposed and implemented to simulate hopper operation in 2D and 3D. The results of a conservation test show that the proposed algorithm conserves energy better than the CP algorithm owing to its straightforward contact calculation. The model then is adopted to simulate the discharge of rod-shaped particles in hopper. Lab-scale experiments were also conducted for DEM model validation. To evaluate the influence of particle shape, outlet opening, and discharge slope angle, rod-shaped particles with triangular, square, pentagonal, and hexagonal cross-sections were used in the experiments and simulation. The results show that the discharge rate of non-spherical particles was significantly affected by the shape of particles, and inter-particle packing property was found to have stronger influence than rolling-related properties, such as roundness or moment of inertia. Conditional clogging phenomena of particles were observed, and the tendency of particle clogging was enhanced by high initial loading, narrow outlet opening, and low slope angle of the hopper outlet. The criteria conditions of particle clogging from experiments were satisfactorily reproduced in the simulation. Although the discharge rate increased with increasing initial loading, the discharge rate saturated at over M = 30 kg owing to the so called Janssen’s effect. The discharge corresponding to the change in particle shape and initial loading was in good agreement between the simulation and experimental results. The comparison of 2D/3D simulation shows that the experiments and simulations successfully minimized the 3D effect.



中文翻译:

料斗中棒状颗粒的排放特性研究:使用多边形/多面DEM的实验和数值研究

在这项工作中,对料斗中大量多边形颗粒的排放进行了数值和实验研究。为此,提出并实施了多边形/多面DEM模型,以模拟2D和3D中的料斗操作。保守性测试的结果表明,该算法由于其直接的接触计算而比CP算法具有更好的节能效果。然后采用该模型模拟料斗中棒状颗粒的排放。还进行了实验室规模的实验以验证DEM模型。为了评估颗粒形状,出口开口和排出斜角的影响,在实验和模拟中使用了横截面为三角形,正方形,五边形和六边形的棒状颗粒。结果表明,非球形颗粒的排放速率受颗粒形状的显着影响,并且发现颗粒间的堆积特性比诸如圆度或惯性矩等滚动相关特性的影响更大。观察到颗粒的条件性堵塞现象,并且通过高的初始载荷,狭窄的出口开口和较低的料斗出口倾斜角来增强颗粒堵塞的趋势。模拟中令人满意地再现了实验中颗粒堵塞的标准条件。尽管放电速率随初始负载的增加而增加,但放电速率在超过 例如圆度或惯性矩。观察到有条件的颗粒堵塞现象,并且通过高初始载荷,狭窄的出口开口和较低的料斗出口倾斜角来增强颗粒堵塞的趋势。模拟中令人满意地再现了实验中颗粒堵塞的标准条件。尽管放电速率随初始负载的增加而增加,但放电速率在超过 例如圆度或惯性矩。观察到颗粒的条件性堵塞现象,并且通过高的初始载荷,狭窄的出口开口和较低的料斗出口倾斜角来增强颗粒堵塞的趋势。模拟中令人满意地再现了实验中颗粒堵塞的标准条件。尽管放电速率随初始负载的增加而增加,但放电速率在超过中号 = 30公斤,归因于詹森效应。颗粒形状和初始载荷的变化所对应的放电与模拟结果和实验结果吻合良好。2D / 3D仿真的比较表明,实验和仿真成功地使3D效果最小化。

更新日期:2020-10-30
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