基于EDEM的粮食立筒仓卸料动态侧压力研究

立筒仓卸料过程中,贮料流态不断变化,仓壁压力随之表现出不同变化规律。为研究卸料过程中贮料在粮食立筒仓中的流动状态和速度分布、贮料对仓壁产生的动态侧压力以及相应超压系数,采用离散元仿真软件EDEM对粮食立筒仓卸料过程进行模拟,分别选定两种不同卸料速度工况,并结合试验结果对比分析动态侧压力。结果表明：通过直接观察和整体流量指数分析筒仓内贮料流动状态,贮料流态与其所处的筒仓位置有关,发展进程为整体流动—管状流动—漏斗型流动；EDEM仿真模拟与试验结果的静态侧压力值接近、动态侧压力分布规律一致,且超压系数误差在合理范围内；卸料整体过程中,流速快工况的超压系数均大于流速慢工况；筒仓仓壁下部1/3hn范围内的动态侧压力突增最为明显,贮料内部不断重复动态拱过程致使仓壁卸料压力呈现不同震荡分布,且该位置的超压系数高于现行规范的水平侧压力修正系数Ch。EDEM离散元卸料仿真进行动态侧压力研究具有可行性,研究成果可为筒仓结构安全设计提供参考。

Dynamic Lateral Pressure of Grain Silo Discharge Based on EDEM

In the process of silo discharge, the flow pattern of storage material changes constantly, and the pressure of silo wall shows different change rules. For studying the flow pattern and velocity distribution, dynamic lateral pressure and corresponding overpressure coefficient during the discharge process, discrete element simulation software EDEM is used to simulate under two different discharge speed conditions, and the dynamic lateral pressure was compared and analyzed combined with the test results. The results show that the flow pattern of the storage material is related to its position by direct observation and overall flow index analysis, and the development process is integrated flow, tubular flow and funnel flow. The EDEM simulation results show that the static lateral pressure value and the dynamic lateral pressure distribution law are consistent with the test results, and the overpressure coefficient error is within a reasonable range. In the whole process of discharge, the overpressure coefficient under the fast velocity condition is greater than that under the slow velocity condition. The dynamic lateral pressure surge is the most obvious in the lower 1/3hn of the silo wall, and the repeated dynamic arch process inside the silo results in different vibration distribution of discharge pressure on the wall, and the overpressure coefficient at this location is higher than the current standard correction coefficient of horizontal lateral pressure Ch. It is feasible to study dynamic lateral pressure by EDEM, and the research results can provide reference for the safety design of silo structures.