基于标准装置的颗粒扩散规律研究

A study on particle diffusion rule based on standard device

针对复杂环境对颗粒检测造成的干扰问题,设计一种颗粒检测的标准装置,此装置参考伽尔顿板对下落球体分布造成的影响,提升颗粒分布均匀性为目标,完善内置孔板的几何模型,通过内置孔板加强颗粒在水平方向上的扩散,使得试验段的颗粒分布更为均匀。对颗粒在标准装置中的扩散过程进行非稳态的数值模拟,利用Fluent仿真软件中的CFD-DEM模型得到颗粒运动过程和浓度变化、流场速度变化云图,并对水平参考面上的颗粒进行均匀性的量化分析。分析结果显示,颗粒在穿越孔板的过程中向外扩散现象明显,促使颗粒在水平方向上分布均匀。经比较各参考面的颗粒分布,颗粒检测的最佳时间在60 s附近,最佳位置在参考面Plane2上下。

A standard device for particle detection is designed to solve the problem of interference caused by complex environment to particle detection. Based on the influence of Galton Plate on the distribution of falling sphere, this device aims to improve the geometric model of the inner orifice plate by improving the uniformity of particle distribution. Moreover, the distribution of particles in the test section become more uniform by strengthening the horizontal diffusion of particles through the inner orifice plate. Unsteady numerical simulation of particle diffusion process of standard device, and make use of Fluent simulation software of CFD - DEM model particle movement and concentration changes and changes in the rate of flow field contours, the quantitative analysis of the uniformity of particles on the surface of the reference level. The results show that the particles diffused outwards obviously in the process of penetrating the orifice plate, which makes the particles distribute evenly in the horizontal direction. By comparing the particle distribution of each reference surface, the optimal time of particle detection is around 60 seconds, and the optimal position is around Plane2 of the reference surface.