一种新型磁选机分选腔的设计及其对流场分布的影响

Design of a New Sorting Chamber of Magnetic Separator and Its Influence on Flow Field Distribution

设计并制造了一种新型磁选机分选腔。针对分选腔内磁选过程中的团聚现象,改进导流板的形状,并应用卡门涡街原理在分选腔内增加阻流体,运用COMSOL Multiphysics分析2种工况对流场分布的影响,得出如下结论:导流板和阻流体均有导流作用;不规则型导流板产生更大的涡流和更多的涡量,易于流体出现涡街现象,带动粒子碰撞,破坏粒子间的团聚现象,提高粒子的松散度;不规则型导流板易于生成大的雷诺数,形成湍流有利于提高气固两相流的充分回旋运动,在分选区域呈现混沌现象;梯形截面阻流体使气流波动更大,涡量更多,颗粒容易受到扰动,呈现松散状态;不规则型导流板和梯形截面阻流体组合配置的分选腔为最佳配置。该研究旨在为改进分选腔提供新思路和新方向。

A new sorting chamber of magnetic separator was designed and manufactured.According to the agglomeration phenomenon in the magnetic separation process in sorting chamber,the shape of the deflector was modified and the bluff body was added in the sorting chamber by the principle of Karman vortex.The influences of two working conditions on the flow field distribution were analyzed by COMSOL Multiphysics and the following conclusions were drawn.The deflector and the bluff body both had a diversion effect.Larger eddy currents and more vorticity would be produced due to irregular deflector,which were prone to vortex phenomenon in fluids,causing particles to collide,destroying agglomeration between particles and increasing the looseness of particles.The irregular deflector was easy to generate a large Reynolds number,and the formation of turbulent flow was beneficial to improve the full swing motion of the gas-solid two-phase flow,showing a chaotic phenomenon in the sorting area.The bluff body with trapezoidal cross-section produced greater airflow fluctuate and more vorticity,and it was easy to disturb the particles,showing a loose state.The sorting chamber with the irregular deflector and the trapezoidal section bluff body was the optimal.This study provided a new idea and a new direction for the improvement of sorting chambers.