Abstract:

The influence of outlet setting on the discharge dynamics of granular material in 2D moving beds was investigated by conducting discrete element simulations. To validate the simulation, a moving bed with single outlet was first modeled. The simulation results showed that the variation of discharge rate was tally with the modified Beverloo, and the variation tendency of the width of funnel zone was in agreement with the experimental data. Based on such validation, the discharge characteristics of granular material in the moving bed with two outlets were then systematically investigated. The simulation results indicated that as to the bed with two same size outlets, the width of funnel zone was simply equal to the sum of the width of funnel zone of the moving bed with one same size outlet, the distance between outlets and the width of outlet, and the granular mass discharge rate was roughly equivalent to that of the moving bed with one same size outlet. For the bed with two different size outlets, increasing the width of large outlet or decreasing the outlet distance was conducive to increasing the discharge rate at small outlet. Nevertheless, the discharge rate at large outlet was not influenced by the small outlet and nearly kept constant.

Key words: moving bed, granular materials, multiple outlet, discrete element method, numerical simula

摘要：

采用离散单元法(DEM)模拟研究了二维移动床出口设置对物料卸料特性的影响。为验证模拟结果的合理性,首先针对单出口移动床进行了模拟研究,模拟结果表明:出口处颗粒质量流率满足修正的Beverloo经验关系式,而且定性上物料层内部流动区宽度随出口宽度的变化规律与实验结果吻合良好。在此基础上对两出口移动床的卸料特性进行了研究,得到以下结论:当出口宽度相等时,物料层内流动区宽度等于单出口条件下流动区宽度、出口间距及出口宽度的加和,而且每个出口处颗粒质量流率与单出口条件下颗粒质量流率相当;当出口宽度不相等时,增加大出口的宽度或减小出口之间的距离有助于提高小出口处颗粒质量流率,但大出口处颗粒质量流率基本保持恒定,不受小出口影响。

关键词: 移动床, 颗粒物料, 多出口, 离散单元法, 数值模拟