涡流空气分级机转笼底盘结构对分级性能的影响

转笼作为涡流空气分级机唯一的动部件，其结构对分级性能有显著影响。采用计算流体动力学软件Fluent 17.0分别对封闭式底盘和开放式底盘两种转笼结构的分级机内部流场进行数值模拟，分析结果表明：开放式底盘结构对环形区流场有分流作用，越靠近环形区底部，分流现象越显著；轴向速度较大会加速颗粒下落，不利于分级精度的提高；分流现象减弱环形区速度场，使开放式的环形区内径向速度和切向速度均小于封闭式底盘结构的速度，在转笼外缘处尤为明显。离散相模拟结果显示，相比于封闭式底盘结构转笼，开放式底盘结构转笼分级粒径更小，分级精度略微降低。对碳酸钙物料进行分级实验的结果与数值模拟结果一致。

Influence of the rotor cage underpan on the classification performance of a turbo air classifier

A rotor cage is the only moving component in a turbo air classifier and its structure has a great influence on classification performance. By using the computational fluid dynamics software Fluent 17.0, the inner flow fields of the turbo air classifier with two different rotor cage underpans have been numerically simulated. The results indicate that there is bypass flow in the annular region when using a rotor cage with an open underpan. Thus the phenomenon of bypass flow becomes more obvious closer to the bottom of the annular region and causes a large axial velocity. This large axial velocity accelerates the falling of the particles, adversely affecting the classification accuracy. In addition, the bypass flow weakens the velocity field in the annular region. Therefore, the radial velocity and tangential velocity for the open underpan are smaller than the corresponding values for the closed one, and this is especially obvious at the outer edge of the rotor cage. Discrete phase simulation results show that the cut size and classification accuracy for the open underpan are smaller than the corresponding values for the closed one. The experimental results for calcium carbonate classification validate the numerical simulation results.