Performance analysis of a gas cyclone with a converging-diverging vortex finder

Abstract

In this study, the influence of a novel converging-diverging (CD) vortex finder on the performance of a gas cyclone was studied using the computational fluid dynamics (CFD) method. In addition, the influence of the CD outlet pipe on the erosion rate of the cyclone was investigated. The cutoff diameter, pressure drop, and erosion rates of the new vortex finder design were compared with those of the conventional straight outlet pipe cyclone. The throat of the CD pipe was at the same level as the cyclone's roof. The simulation showed that the CD outlet pipe significantly reduced the cyclone pressure drop. The height and diameter of the converging part of the vortex finder affected the cyclone pressure drop and separation efficiency. Increasing the converging part's inlet diameter reduced the outer vortex tangential velocity and the cyclone separation efficiency. Increasing the converging part inlet diameter reduced turbulent intensity at different cyclone levels. The CD vortex finder with the shortest height and inlet diameter of the converging part (model C1) reduced the cutoff diameter from 6.2 µm to 5.9 µm. The CD outlet pipe with the largest height and inlet diameter of the converging part (model C6) reduced the pressure drop by 42.2% compared to the conventional cylindrical vortex finder. The erosion rate also decreased significantly with an increase in the converging part inlet diameter. However, the converging part height only slightly affected cyclone performance.