Li Tongqing, Peng Yuxing, Zhu Zhencai, Zou Shengyong, Yin Zixin
School of Mechatronic Engineering, China University of Mining and Technology, Xuzhou 221116, China.
Jiangsu Key Laboratory of Mine Mechanical and Electrical Equipment, China University of Mining and Technology, Xuzhou 221116, China.
Materials (Basel). 2017 May 11;10(5):520. doi: 10.3390/ma10050520.
Aiming at predicting what happens in reality inside mills, the contact parameters of iron ore particles for discrete element method (DEM) simulations should be determined accurately. To allow the irregular shape to be accurately determined, the sphere clump method was employed in modelling the particle shape. The inter-particle contact parameters were systematically altered whilst the contact parameters between the particle and wall were arbitrarily assumed, in order to purely assess its impact on the angle of repose for the mono-sized iron ore particles. Results show that varying the restitution coefficient over the range considered does not lead to any obvious difference in the angle of repose, but the angle of repose has strong sensitivity to the rolling/static friction coefficient. The impacts of the rolling/static friction coefficient on the angle of repose are interrelated, and increasing the inter-particle rolling/static friction coefficient can evidently increase the angle of repose. However, the impact of the static friction coefficient is more profound than that of the rolling friction coefficient. Finally, a predictive equation is established and a very close agreement between the predicted and simulated angle of repose is attained. This predictive equation can enormously shorten the inter-particle contact parameters calibration time that can help in the implementation of DEM simulations.
为了预测磨机内部的实际情况，离散元法（DEM）模拟中铁矿石颗粒的接触参数应准确确定。为了准确确定不规则形状，采用球体团聚法对颗粒形状进行建模。系统地改变颗粒间的接触参数，同时任意假定颗粒与壁面之间的接触参数，以便纯粹评估其对单一尺寸铁矿石颗粒休止角的影响。结果表明，在所考虑的范围内改变恢复系数不会导致休止角有任何明显差异，但休止角对滚动/静摩擦系数具有很强的敏感性。滚动/静摩擦系数对休止角的影响是相互关联的，增加颗粒间的滚动/静摩擦系数可明显增大休止角。然而，静摩擦系数的影响比滚动摩擦系数更为显著。最后，建立了一个预测方程，预测的休止角与模拟的休止角之间达成了非常紧密的一致性。该预测方程可极大地缩短颗粒间接触参数的校准时间，有助于离散元法模拟的实施。
