涡流空气分级机内湍流涡频谱对其性能的影响

依据湍流基本概念和涡频谱基本理论 ,讨论了涡流空气分级机内不同频率、不同尺度的湍流涡对物料分散和分级精度的影响 ,提出高频脉动的小尺寸湍涡有利于团聚体解吸、粉料的分散 ,能提高物料分级精度和分级效率。在不改变转笼外边缘和导流叶片内边缘间环形区宽度的情况下 ,通过在转笼外边缘分别沿径向叶片圆周呈90°角对称加四根杆 ,改变环形区湍流涡频谱分布 ,增加高频小湍涡 ,使得分级精度指数分别从 0.71,0.62提高到0.80 ,0.76 ,相对提高 12.7%和 22.6 %。

The effect of frequency spectrum of the eddies of turbulent flow in a turbo classifier on its classification characteristics

Based on the fundamental concept of turbulent flow and the theory concerning the eddy frequency spectrum, the effects of various frequency sections in turbo classifiers on the dispersing of the powder aggregates and classifying precision were discussed. The authors point out that the eddies of small scale and high frequency contribute to destroying the powder aggregates and improving the powder dispersing extent. This renders classifying precision improvement and an increase in efficiency. In order to modify the frequency spectrum of turbulent eddies, a device which was expected to increase the turbulent eddies of small scale and high frequency, with the width of the annular region unchanged, was fitted in the annular region between the outside borderline of the rotor cage and the inside borderline of the baffle blades in the turbo classifier. The experiment results indicate an increase in the index d 25/d 75 of the classification precision from 0.71 and 0.62 to 0.80 and 0.76.