The CFD method was employed to simulate the back mixing of particles in a guide vane separator based on the Reynolds stress model (RSM)and the discrete particle model (DPM).The results show that the back mixing of particles is serious at the bottom of the dust discharge

which contains 38% of the total mass of particles.The mass flow rate of back mixing of particles in the dust discharge is 47% of the total mass flow rate.The back mixing of particles decreases sharply at 1.1D above the dust discharge

where D is the diameter of cyclone.The particle back mixing that affects cyclone efficiency is only 2.5% of total inlet mass flow rate of particles.The particles smaller than 13 μm affect the total efficiency.Smaller particles result in more significant influence.