颗粒离散单元法数值模拟与典型实验对比研究

Comparative Study Between Numerical Simulation by Discrete Element Method and Typical Experimental Research of Particles

为了验证离散单元法的可靠性,尤其是Hertz-Mindlin模型参数设置的准确性,进行颗粒装填孔隙率、颗粒下落弹跳、颗粒堆积倾斜休止角3个典型颗粒行为的数值模拟及实验对比研究。结果表明:自由落体的玻璃颗粒装填后的孔隙率先随颗粒装填数量的增加而减小,然后基本保持不变,与实验结果吻合;颗粒碰撞弹跳模拟可得到和实验一致的颗粒自由落体高度变化图;颗粒的粒径越小,休止角越大,与数值模拟定量吻合,颗粒数量需要达到一定范围,休止角才能准确测量;离散单元法和Hertz-Mindlin模型的可靠性得到验证,并给出一套模拟参数设置,可用于颗粒其他行为的深入研究。

The experiment of measuring the particle porosity, falling- bouncing behavior and the angle of repose was carried out for the verification of the reliability of DEM method and the accuracy of Hertz- Mindlin contact model, especially the parameter values used in the model. The results show that the porosity of free-falling glass particles decreases with the particle numbers at the beginning, then remains unchanged for the influence of particle gravity action and close packing. The simulated bouncing behavior of free-falling glass particles agrees with the experiment results exactly. The repose angle of the glass particles decreases with the particle diameter, which also keeps consistent with the experiment results quantitatively. The number of particles should be large enough to ensure the accuracy of the angle of repose. The accuracy of Hertz-Mindlin contact model is validated, DEM method is found to be a good tool to investigate particle behavior, and a group of Hertz-Mindlin model parameter values are recommended for studying other behaviors of glass particles in the future.