细颗粒物在旋风分离器内流动特性

Flow characteristics of particles in cyclone separator

为了研究操作条件和颗粒特征对细粉体颗粒在旋风分离器中流动状态的影响,文中采用欧拉-拉格朗日方法对细颗粒在旋风分离器内的停留时间进行模拟计算。探究入口气速、粉体粒径和固气比对粉体在旋风分离器内的停留时间分布密度函数、平均停留时间和停留时间量纲一方差的影响。结果表明:粉体颗粒在旋风分离器内部的停留时间分布密度函数总体呈正态分布;当入口气速u=10 m/s时,粉体颗粒平均停留时间为0.40 s,停留时间量纲一方差为0.11,此时粉体颗粒平均停留时间最长,颗粒运动状态更接近平推流;在模拟工况范围内,随着粉体粒径增大,停留时间量纲一方差增大,颗粒在旋风分离器内的返混程度加剧;颗粒粒径和固气比变化对平均停留时间影响较小。

To study the effect of operating conditions and particle characteristics on the flow state of particles in a cyclone separator, Euler-Lagrangian method was used to simulate and calculate the residence time of particles. The influence of inlet gas velocity, particle size and solid-gas ratio on the residence time distribution(RTD), mean residence time(MRT) and dimensionless variance were explored. The results indicate that the residence time distribution density function of the particles in the cyclone separator shows a normal distribution nearly. When the inlet gas velocity u is 10 m/s, the average residence time of particles is 0.40 s, and the dimensionless variance of the residence time is 0.11. Under this condition, the average residence time of particles is the longest, and the particle motion state is closer to the flat push flow. Within the range of simulated working conditions, as the increase of particle size, the dimensionless variance of the residence time increases, and the level of backmixing of the particles in the cyclone separator is improved. The average residence time is almost not affected by the change of particle size and solid-gas ratio.