螺旋分选机流场及颗粒运动的数值模拟研究

Numerical simulation of flow field and particle motion behavior in spiral separator

采用CFD-DEM单向耦合的数值模拟方法研究了螺旋分选机的流场和颗粒的运动特性,实验和模拟分析了1～1.5 mm粒级煤粒的分选过程.结果表明:水流在首圈回转过程中,水膜外缘不断增厚,内缘不断变薄.颗粒随水流进行回转运动,低密度颗粒悬浮在流膜上层,中高密度颗粒呈滚动或跳跃状态.密度、粒度和入料流量对颗粒的回转半径影响显著,当回转角度小于120°时,不同尺度颗粒的运动轨迹基本一致;回转角度大于120°后,密度和粒度越大的颗粒回转半径越小.入料量为3.0 m^3/h时,低密度颗粒和高密度颗粒回转半径差减小至14.07 mm.入料流量对螺旋分选机的分选密度影响明显,对不完善度影响较小.

Numerical simulation of unidirectional coupling CFD and DEM was adopted to study the flow field and particle motion characteristics of the spiral separator. Experiment and simulation analysis of the separation process of 1-1.5 mm coal particles was conducted. The results show that during the first rotation of the water flow, the thickness of the outer edge of the water film increases continuously, while the thickness of the inner edge decreases continuously. The particles move in a circular motion with the water flow. The low-density particles suspend in the upper layer of the flow film, while the medium-high-density particles are in a rolling or jumping state. Density, particle size and feed rate have significant effect on the rotating radius of the particles. When the rotation angle is less than 120°, the movement of particles with different particle sizes and density are basically the same. When the rotation angle is greater than 120°, the particles with larger density and particle size would have smaller rotating radius. When the feed rate is 3.0 m^3/h, the difference in rotating radius between the low-density particles and the high-density particles reduces to 14.07 mm. The feed rate has a significant effect on the separation density, but little effect on the imperfection.