EFFECT OF BLOW-DOWN ON FLUID-FLOW AND PARTICLE MOVEMENT IN CYCLONE CLASSIFIER

Three-dimensional numerical simulation and experimental studies have been conducted on the fluid flow and particle movement in a cyclone classifier with blowdown. By use of the blow-down method, the downward velocity component near the conical wall becomes larger than the case without blow down. In the case of the blow-down method, the particles collected on the conical wall move to the dust box smoothly and 50% cut size decreases. It was also confirmed by the simulation that particles of small diameter enter the dust box first, but they eventualy exit the box in the case without blow-down. In the case of blow-down, particles of small diameter are aspirated into the blow-down tube and re-entrainment of particles from the dust box can be suppressed. From the experimental and theoretical studies, it was also found that the partial separation efficiency with small inertia tends to become constant in the case of the brow-down method.