涡流分级机转笼结构改进及内部流场数值模拟

引言 随着科技的进步,各行各业对粉体粒径和粒径分布的要求向细而窄的方向发展,因此对分级设备提出了高效、高精度的性能要求.涡流空气分级机是20世纪70年代末日本发明的,属于第三代动态干式分级机,具有能耗低、流场稳定等特点,广泛应用于建材、精细化工、食品、医药以及矿物加工等领域.

Improvement on rotor cage structure of turbo air classifier and numerical simulation of inner flow field

In order to obtain fine powder with narrow particle size distribution and improve classification precision, the full blades in conventional rotor cages were improved to splitter style.The effect of the structure of the rotor cage with full blades and with splitter blades on the inner flow field of a turbo air classifier was investigated with the software Fluent.The result from numerical simulation indicates that air velocity fluctuations on outer cylinder of the improved rotor cage are decreased in the height direction, while, the radial velocity is decreased and the tangential velocity is increased compared with the conventional rotor cage, so the cut size of classified particles is smaller.The deviation of tangential velocity and radial velocity distribution on outer circle of horizontal section of the rotor cage is greatly improved, compared with the conventional rotor cage.When the ratio of the short blade length to the long blade length is 0.77, the flow field between blades is stable, and the velocity distribution on outer circle of the rotor cage is uniform.The experiment results on material classification demonstrate that the rotor cage with splitter blades is helpful to improving the classification precision and decreasing the cut size.The experimental result presents qualitative evidence for the CFD simulation and the feasibility in engineering applications.