The pneumatic conveying system of coal particles can greatly reduce the dust and improve the environmental quality at underground mining workface and the surrounding of coal enterprises. The particle shape and the interaction coefficients between particles and the contact surface play important roles in the pneumatic conveying and CFD–DEM simulation. In order to build the semblable shape models and obtain the accurate interaction coefficients of large coal particles, this article establishes the contact model by the particle overlap method and describes the mathematical model of the shape characteristics for large coal particle. The particle models are simulated by adopting the multi-index mixed orthogonal experiments. The accumulation density, the porosity and the error between simulation and experiment are taken as the indexes, and the particle models and the particle contact coefficients are taken as the orthogonal test factors. As a result, three more accurate particle models and their interaction coefficients are obtained, which provide the model basis for the pneumatic conveying of large coal particles.

煤粉气力输送系统可以大大减少粉尘，改善地下采煤工作面及煤炭企业周围的环境质量。颗粒形状以及颗粒与接触表面之间的相互作用系数在气动输送和CFD–DEM模拟中起着重要作用。为了建立可组装的形状模型并获得大煤颗粒的准确相互作用系数，本文采用颗粒重叠法建立了接触模型，并描述了大煤颗粒形状特征的数学模型。采用多指标混合正交实验对颗粒模型进行了模拟。以堆积密度，孔隙率和模拟与实验之间的误差为指标，并以颗粒模型和颗粒接触系数为正交试验因子。结果，获得了三个更精确的颗粒模型及其相互作用系数，为大颗粒煤的气动输送提供了模型基础。