Experimental fluid dynamic characterization of a cyclone chamber

Abstract

An experimental investigation was performed on a laboratory scale model of a gas cyclone separator inserted in a closed/open loop test facility built up to study the flow field of both the gas and solid phase. The cyclone is made entirely by plexiglas in order to allow optical access for velocity measurements through laser Doppler velocimetry. Three velocity components of the gas phase were measured inside the various regions of the apparatus (tangential inlet chamber, cylindrical body and exhaust duct) and a preliminary analysis of the solid phase behaviour has been carried out in some restricted regions of the device, identified as critical for the separation process. Experiments were performed at fixed geometrical swirl number ( S=2.39) in the correspondence of two inlet Reynolds numbers ( Re=3.76×10 4 and 1.25×10 5); glass particles of mean diameter d p=37 μm were added to the fluid flow to simulate the solid phase behaviour. The measurements performed put into evidence the presence of fluid dynamic instabilities (vortex breakdown and precessing vortex core in the exhaust flow) induced by the high swirling motion inside the device and a possible solution to reduce this problem has been identified. Preliminary analysis of the solid phase motion clearly showed the particles behaviour in selected regions of the apparatus and allowed to understand the details of the gas–solid phase separation effects.