Effect of free air inflow method on fine particle classification of gas-cyclone

Abstract The effect on particle separation performance using a free air inflow cyclone at the upper plate was examined by experiment and CFD simulation. The 50% cut size with the free air inflow cyclone is smaller than that without the free air inflow cyclone under the same pressure drop condition. The optimum flow ratio defined by the free air inflow rate to main flow rate is 0.4. The four slit inlet cyclone shows better particle separation performance compared to other types. For a flow ratio greater than 0.4, the 50% cut size increases again due to the decrease of the main flow rate. From the simulation results, the rotational and downward flow velocity in the upper cylindrical part with the free air inflow cyclone is greater than that without the free air inflow cyclone. In the case of the free air inflow cyclone, a particle trajectory simulation indicated that particles entering the cyclone tend to move to the circular wall region smoothly. The experimental and simulation results indicate higher particle separation performance for the free air inflow cyclone.