基于离散元EDEM的米粒破碎特性分析

Analysis of rice grain breakage characteristics based on discrete element EDEM

目的:优化碾米机碾辊转速,减少碾白过程中米粒的碎米率。方法:利用SolidWorks软件建立挤压填充模型,采用EDEM软件中颗粒黏结模型建立单粒米粒以及两粒米粒碰撞接触模型,模拟不同含水率的米粒在不同下落速度下的碰撞过程,观察相应米粒碰撞结果。结果:米粒在碰撞过程中有3种临界状态,分别是完整米粒、轻微破碎米粒、断裂米粒。在设定的含水率范围下,米粒破碎率随着含水率和碰撞速度的增加而增加;单粒米粒和两粒米粒碰撞模型中完整米粒状态的临界破碎速度相近,分别为23.5,22.0 m/s。结论:速度和含水率对米粒破碎形态影响显著,并且在含水率为10.6%下,米粒不破碎能承受的最大速度为22.0 m/s,此时米粒破碎率较小且满足碾白需求。

Objective: The rotational speed of the roller of the rice mill was optimized to reduce the crushing rate of rice grains in the process of whitening. Methods: The extrusion filling model was established by using SolidWorks software, and the collision contact model of single rice grain and two rice grains was established by using the particle bond model in EDEM software. The collision process of rice grains with different moisture content at different falling speeds was simulated, and the collision results of corresponding rice grains were observed. Results: There were three critical states of rice grains in the process of collision, which were intact rice grains, slightly broken rice grains and broken rice grains. Under the set moisture content range, the crushing rate of rice grains increased with the increase of moisture content and collision velocity, and the critical crushing rates of intact rice grains in the collision model of single grain and two grains were similar, which were 23.5 m/s and 22.0 m/s, respectively. Conclusion: The speed and moisture content have a significant effect on the crushing morphology of rice grains, and when the moisture content is 10.6%, the maximum speed of non-crushing of rice grains is 22.0 m/s, at this time, the crushing rate of rice grains is small and meets the demand of milling.