基于EDEM的料斗半锥角与颗粒粒径对煤颗粒的排料性能影响

Study on the influence of hopper half cone angle and particle size on coal particle discharge based on EDEM

实验基于料斗结构对煤在其内部的排料影响,利用离散元软件EDEM分析不同半锥角的料斗中煤颗粒系统的流动行为差异。建立3种直径的煤粉颗粒与5个半锥角的料斗模型,分别模拟分析了料斗内部颗粒流型以及颗粒流动状态和料斗半锥角间的映射关系,颗粒受力变化与料斗半锥角以及颗粒直径的映射关系。结果表明:料斗半锥角不仅对内部颗粒流型有着明显的影响,并且颗粒流动状态随着半锥角的增大呈现局部涡流状。1 mm直径的颗粒在中心流型中依然能保持良好的流动均匀性,而颗粒煤粒径越大,在排料过程中更容易出现明显的平移、斜移以及交叉等流动现象,料斗半锥角的增大会使得颗粒在流动时出现连续起伏的受力变化。壁面附近的慢速颗粒更容易以局部涡流形态沿着料斗呈曲线式运动,降低下料效率,加剧排料过程中的不均匀下料情况。

In this paper, based on the influence of hopper structure on coal discharging in its interior, the flow behavior of hopper with different semi cone angles on coal particle system was analyzed by using the discrete element software EDEM. A hopper model with three diameters of pulverized coal particles and five half cone angles was established, and the mapping relationship between the flow pattern of particles in the hopper and the flow state of particles and the half cone angle of the hopper, as well as the mapping relationship between the change of particle force, the half cone angle of the hopper and the particle diameter were simulated and analyzed respectively. The results show that the semi cone angle of the hopper not only has an obvious effect on the internal particle flow pattern, but also the particle flow state presents a local eddy current with the increase of the semi cone angle. The particles with a diameter of 1mm can still maintain good flow uniformity in the central flow pattern. The larger the particle size is, the more likely it is to appear obvious flow phenomena such as translation, oblique movement and cross in the discharge process. The increase of the hopper half cone angle will make the particles have continuous fluctuating force changes when flowing. Slow particles near the wall are more likely to move along the hopper in a curve shape in the form of local eddy current,reducing the blanking efficiency and intensifying the uneven blanking during the discharging process.