Abstract: Aiming at the problem of the heavy particles passing through the overflow outlet because of short-circuit flow, which is existed in the current running cyclone, a cyclone with a arc overflow pipe was proposed , and the numerical simulation and experimental research were carried out. The simulation results show that the arc structure of the overflow pipe can be used to move outward the transitional region at the bottom of the overflow hole, improve the tangential velocity of the fluid in this area, thus increasing the centrifugal strength , guiding the short-circuit flow to the external swirling flow to participate in the separation again, which helps to achieve the aim of reducing coarse particles mixed in the overflow. The experimental results show that under the same outlet ratio, the content of -25 μm particles in the overflow and the comprehensive classification efficiency for the arc overflow pipe cyclone are higher than those of the linear type overflow pipe cyclone. The best inhibitory effect of arc overflow pipe cyclone occurs when the outlet ratio is 0.33, and the corresponding overflow concentration is 4.72%, the content of -25 μm particles in the overflow is 98.37%, and the comprehensive classification efficiency of -25 μm particles is 78.92%. These indexes are higher than those of the linear type overflow cyclone, which are 4.25%, 96.86% and 73.51% respectively.

Key words: Cyclone, Short-circuit flow, Arc overflow pipe, Comprehensive classification efficiency