Abstract: Taking two different types of cyclones as the research object, the solid particles before and after separation were sampled and the particle diameter was analyzed in order to study the separation efficiency. The two cyclones were modeled separately and the incline angle of the cyclone inlet and the height of the vortex finder were changed, and the separation efficiency was calculated by numerical simulation. The simulation results show that the error between the simulation and experiment calculation results is within 15%, which verifies the accuracy of the results. The proper increase of the vortex finder height can improve the separation efficiency of cyclones. The pressure drop at the inlet and outlet increases first and then decreases with the increase of the height of vortex finder. The increase of incline angle of the inlet is beneficial to improve the separation efficiency of these two types of cyclones. After comprehensive consideration of the impacts on the inlet and outlet pressure drop of the cyclones, it is considered that the optimal s/a (the ratio of s \[the height of vortex finder of the cyclone\] to a \[the entrance height of the cyclone\]) of the compact cyclone is about 0.5 while that of the hot cyclone is about 0.75. The incline angle of the inlet of the compact cyclone should be about 10° while that of the hot cyclone should be about 15°. The above conclusions can be used to guide the structure optimization and transformation of cyclones.

Key words: cyclone, separation efficiency, pressure drop, numerical simulation, structure optimization