CHARACTERIZATION OF THE PVC PHENOMENA IN THE EXHAUST OF A CYCLONE DUST SEPARATOR

A laboratory scale cyclone dust separator with swirl numbers varying f rom 3.043 to 1.790 was used to examine the effects of different downst ream pipework configurations, flowrates and swirl numbers upon the siz e, shape, and position of the precessing vortex core. Also examined wa s the effect the precessing vortex core had on the reverse flow zone, and the relationship between the two. It was concluded that the revers e flow zone displaced the central vortex core to create the precessing vortex core. The reverse flow zone would then provide feedback for th e precessing vortex core, and precess around the central axis about 30 degrees behind the precessing vortex core (P.V.C). The size and posit ion of the P.V.C was effected by changes in Reynolds number, and any a dditions of downstream systems to the cyclone would also affect the st rength of the P.V.C. The P.V.C would squeeze and accelerate the flow t hrough a constriction set up between the outer limits of the core and of the exit diameter wall. Spiral engulfment vortices were produced on the outside of the flow and served as the initial entrainment mechani sm for external flow.