颗粒流撞击壁面的离散元模拟

为了解决催化裂化装置中催化剂颗粒的磨损、撞碎等问题，首要解决催化剂颗粒的运动特性问题，为此将离散元数值模拟的技术应用到催化剂颗粒撞击壁面的模型中，简化了催化剂颗粒撞击壁面的模型为颗粒流撞击壁面模型，开展了颗粒流撞击壁面的离散元分析；建立了颗粒流中随机标记颗粒的速度与时间、位移与时间的关系，及整个颗粒流的动能与时间的关系；追踪了标记颗粒的运动轨迹，解释了颗粒流撞击壁面产生不规则分布的原因；提出了分段区间随机取样求得壁面平均应力的方法，在不同入射速度下对壁面产生的平均应力大小进行了对比分析。研究结果表明，入射颗粒流的速度对壁面应力的影响呈不稳定性，不同的入射速度影响壁面的平均应力大小，且在一定范围内入射速度越大，壁面的应力越大。

Simulation of particle flow impact wall based on DEM

In order to solve the problems of wear and tear of the catalyst particles, in catalgtic cracking unit the first thing is to solve the problem of particle＇s motion feature, the numerical simulation method of discrete element method（DEM） was applied to the catalyst particles impinging wall model. The model of the catalyst particles impinging on the wall surface was simplified as the parlicle flow impinging wall model. The discrete element analysis of particle flow impinging on the wall surface was carried out. The relation between velocity and time, displacement and time, and relation between kinetic energy and time of particle flow was established. The marked particle＇s tacking was tacked. The reason for particle irregular distribution was explained. A method was presented to a random sample in subsection interzone seek to wall＇s average stress. Different incident speed of the effect of stress was compared and analyzed. The simulation results show that different incident speed has an unsteady influence on wall stress, different incident speed has an effect on the size of the wall stress and the bigger of incident speed, the bigger of wall stress in an certain range.