Authors

Abstract

The transportation, distribution, and collision dynamics behaviors of rice grains in the polishing machine critically influence the polishing performance. However, existing research has predominantly concentrated on the polishing mechanisms of laboratory-scale polishing machines, where deviations induced by scaling effects are inherently present. This study utilizes the discrete element method to numerically simulate the operational dynamics of industrial-scale rice polishing systems, with subsequent experimental validation confirming the simulation's reliability. The movement characteristics of the particles in the polishing chamber were analyzed, and the influence mechanism of the key components of the sieve on the particle movement was revealed. The simulation results show that as the gap between the polishing roller and the rice sieve increases, the number of particles in the polishing chamber increases, while the axial, tangential and combined velocities of the rice grains as well as their velocity fluctuations decrease, thereby reducing the uniformity of transportation and the collision intensity. Furthermore, influenced by the gravitational force of the rice grains, the movement of the rice grains in the horizontal polishing machine exhibits a certain degree of irregularity. This radial irregularity in the movement promotes the alternation of the rice grains between the inner and outer rings, thereby enhancing the uniformity of the polishing of the rice grains. This research provides theoretical support for the structural design and process optimization of rice polishing equipment.

Abstract in Chinese

抛光机内米粒的输送、分布及碰撞等动态行为对抛光效果起着至关重要的作用。然而，既有研究多聚焦于实验室级抛光机的抛光规律，不可避免地存在规模效应导致的偏差。本研究采用离散元法模拟了工业规模的抛光机工作过程，并通过台架试验验证了仿真的可靠性。分析了抛光室内颗粒的运动特性，并揭示了米筛关键部件对颗粒运动的影响机制。仿真结果表明，随着抛光辊与米筛间隙的增加，抛光室内颗粒数量增加，米粒的轴向、切向和合速度及其速度波动随之减少，从而使其输送均匀性及碰撞强度降低。此外，受米粒重力的影响，米粒在卧式抛光机中的运动呈现出一种不均匀性，这种径向运动的不均匀性促进了米粒在内外圈的交替，促进了米粒的抛光均匀性。本研究为大米抛光设备的结构设计与工艺优化提供了理论支撑。