中文摘要：

涡流空气分级机分级粒径主要受转笼转速与入口风速匹配关系的影响。入口风速一定时,转笼转速越高,分级粒径越小,但这会造成流场速度分布不均匀,而降低分级精度。利用Fluent软件对具有直叶片转笼结构的涡流空气分级机进行建模和数值模拟,分析转笼内流场特性,针对其流场不均匀及转笼入口冲角大等现象,对转笼叶片的形状及安装角进行改进,提出一种圆弧形叶片转笼的设计方法。通过数值模拟及物料试验对改进结果进行验证,数值模拟结果表明：圆弧形叶片转笼入口冲角减小,流道内流场更加均匀,分级粒径减小。碳酸钙分级试验结果与数值模拟结果吻合：设计工况即入口风速为12 m/s,转笼转速为1200 r/min时,采用设计的圆弧形叶片转笼在保持分级精度不变的情况下,分级粒径减小了11.5%。

英文摘要：

The classification performance of a turbo air classifier is mainly affected by matching of air inlet velocity and rotating speed of rotor cage. With the same inlet velocity,increasing the rotating of rotor can decrease cut size to obtain ultra-fine powders. However,it will cause non-uniform distribution of fluid flow and decrease classifying accuracy. A model of the turbo air classifier with straight-blade rotor cage is established and the flow field is simulated by the software of Fluent. To solve the problems including non-uniform distribution of fluid flow and big angle of fluid-attack at the entrance of rotor cage,the blade＇s shape and installation angle are designed and improved. A method of designing arc-blade rotor cage is proposed. The simulation results indicate that for the arc-blade rotor cage,the angle of fluid-attack at the entrance of rotor cage is decreased,the flow field of channel in rotor cage becomes uniform,and the cut size is also reduced. Calcium carbonate classification experimental results are in agreement with simulation results. In the design condition that air inlet velocity is 12 m/s and rotating speed of rotor is 1 200 r/min,compared to the straight-blade rotor cage,the cut size is reduced 11.5% by using the turbo air classifier with arc-blade rotor cage without decreasing the classifying accuracy.