Study On Method Of Suppressing Particle Deposition On The Outer Wall Of Vortex Finder

Cyclone separators have become one of the most commonly used gas-solid separation equipment due to their high separation efficiency,simple structure,and low cost.However,the deposition of particles on the outside of the vortex finder and the coking problem it brings have always affected the normal long-term operation of the separator.This article designs a cyclone separator with secondary air flow based on the idea of protecting the vortex finder with near wall swirling flow.The characteristics of flow field and particle deposition of the ordinary and improved cyclone separators are compared and analyzed.The self-cleaning phenomenon and its causes at the top of vortex finder are studied.The main content and conclusions are as follows:(1)Using numerical simulation methods,the distribution of flow field in the separator before and after the addition of secondary air flow was studied.The results showed that secondary air flow mainly affects the flow field around the vortex finder and has almost no effect on the flow field of the cylinder and cone.The secondary air flow forms a rotating air flow barrier on the outer side of the vortex finder,which can block the particle containing air flow from approaching the vortex finder,and also play a secondary separation role for fine particles,creating favorable flow field conditions for reducing particle deposition.(2)By comprehensively analyzing the flow field and particle deposition of improved separators with different flow channel width and extension height,the optimal structural parameters for the vortex generator were determined to be a width of 10 mm and an extension height of 50 mm.Compared with ordinary separators under the same operating conditions,the particle deposition mass on the outer side of the vortex finder is reduced by about 60%,the deposition area is reduced by about 13%,and the separation efficiency and pressure drop are slightly improved.It was found that the deposition and peeling of particles on the outer side of the vortex finder occurred simultaneously.(3)The existence of a self-cleaning area on the outer side of the vortex finder under different inlet velocities,particle concentrations,and particle types was determined through experiments,and the air flow in this area has scouring ability.Through numerical simulation,it was found that the air flow in the self-cleaning zone is relatively small.Preliminary analysis shows that the reason for its formation is the low concentration of particles in the area,difficulty in reaching the outer wall of the vortex finder,and certain scouring ability of the air flow.