| Abstract
| - In this paper the flow pattern in a tangential inlet cyclone is studied by laser Doppleranemometry, with emphasis on the inlet region. The particular focus is on axial asymmetry inthe flow, which was studied by determining radial profiles of the axial and tangential gas velocitycomponents at four different angular positions. This was done at each of four axial flow stations.The results are shown graphically, discussed, and compared with the literature; in particular,they are compared with two studies: (a) an experimental investigation of the boundary layerflow in cyclones and (b) a study based on three-dimensional computational fluid dynamics (CFD)simulations. The results presented in this paper expose regions where the gas velocity differsconsiderably from that normally held to exist. Although the results generally agree qualitativelywith numerical simulations, they differ considerably quantitatively: they show less axialasymmetry than do the CFD simulations. The results support the notion put forward by someother workers that a recirculatory flow pattern in the axial/radial directions exists in the upperpart of the inlet region associated with secondary flows induced by the swirling motion in theboundary layer by the cyclone lid. This feature may have profound influence on the separationefficiency. The likely effects of the flow features on the separation efficiency of the cyclone andits reliability are discussed.
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