涡流空气分级机环形区三维流场模拟研究

Simulation and study on 3D flow fields of annular regions in turbo air classifier

为了探明涡流空气分级机内流场的特性,在分级机的转笼外缘对称安装平行竖杆,利用FLUENT软件对安装不同数量平行竖杆的分级机的环形区三维流场进行数值模拟。研究结果表明:安装平行竖杆可以提高环形区的湍流耗散率,有利于粉体在环形区的分散;分别增加2、4、6、12根平行竖杆,可以使转笼外外柱面气流的切向、径向速度更加均匀,轴向速度减小,且惯性反旋涡现象减弱,从而提高分级精度;与其他数量平行竖杆的分级机相比,对称增加2根平行竖杆分级粒径较小。涡流空气分级机转笼外缘安装平行竖杆的流场模拟分析结果与已有的物料试验相符,安装平行竖杆的分级机具有性能优良且结构简单的特点。

To investigate the characteristics of inner flow fields in turbo air classifiers, parallel vertical stems were installed symmetrically on the periphery of the rotor cage in a turbo air classifier. Software FLUENT was applied to conduct the numerical simulation on 3D flow fields of annular regions in classifiers with various numbers of parallel vertical stems. The results showed that： the installation of parallel vertical stems was help- ful to increasing turbulent dissipation rate of annular regions, which was conducive to powder dispersion in an- nular regions; for the classifiers with 2, 4, 6, 12 parallel vertical stems respectively, the distribution of radial and tangential air velocity on the periphery of the rotor cage was more uniform and the axial velocity, decreased, and the counter-rotating vortex weakened, in result the classification precision increased： Compared with the classi- fiers with the other numbers of parallel vertical stems, the classifier with 2 parallel vertical stems produced the finer classified particles. The simulation results coincided with present material experiments. Therefore, it was concluded that the classifiers with parallel vertical stems had high performance and simple structure.