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为了研究活性焦颗粒在移动床内的流动特性,通过离散单元法直接数值模拟方法对活性焦即圆柱形颗粒在移动床内的流动进行了数值模拟。采用多元颗粒模型来描述圆柱形颗粒,即圆柱形颗粒通过几个叠加在一起的球元构成。建立了圆柱形颗粒的碰撞机制,分析了圆柱形颗粒在流动时的受力情况,并通过实验验证多元颗粒模型的可靠性。从宏观和微观2个方面,比较圆柱形颗粒2种构建方式(2球元和3球元)下的模拟结果。结果表明:2球元和3球元构建的圆柱形颗粒在动能、转动动能、变形量、碰撞力、碰撞次数等微观方面的差别较大。且通过比较颗粒位置图和下料率可以看出,3球元圆柱形颗粒的模拟结果与实际结果更加相符,因此,选择3球元作为圆柱形颗粒的构建方式。
In order to study the flow characteristics of the activated coke particles in a moving bed, the numerical simulation of the flow of the activated coke, ie, the cylindrical particles, in a moving bed was carried out by using the direct numerical simulation method of discrete element method. Multivariate particle model is used to describe cylindrical particles, that is, the cylindrical particles are composed of several spherical elements superimposed together. The collision mechanism of cylindrical particles was established, the force of cylindrical particles flowing was analyzed, and the reliability of multivariate particle model was verified by experiments. From two aspects of macroscopic and microscopic, the simulation results of two kinds of construction methods of cylindrical particles (2-ball and 3-ball) are compared. The results show that the cylindrical particles formed by 2-ball and 3-ball have great difference in kinetic energy, rotational kinetic energy, deformation, impact force and collision frequency. And by comparing the particle location map and blanking rate, we can see that the simulation results of 3-ball cylindrical particles are more consistent with the actual results. Therefore, we choose 3-ball as the construction method of cylindrical particles.