Liquid film breakup pattern and optimization of vane-type separator

Abstract

The formation of liquid film and fragmentation downstream of swirler in vane-type separators, which is the key phenomena affecting the separation efficiency, is not well understood. To reveal the film breakup mechanism and the distribution characteristics of liquid film at the outlet of swirler, a visual vane-type separator test facility has been developed. By high-speed camera from the top, serious film breakup occurs in the rear of arc-vane swirler due to liquid accumulation on the hub and vanes is captured. While both bag breakup and ligament breakup are the dominant film breakup types, bag breakup resulting in divergent secondary droplets prolongs the gas–liquid separation path and is the main threaten to achieve high separation efficiency. New swirler using tilted-flat vanes with micro-pillars are proposed to guide the liquid film to migrate towards the wall of the riser and suppress liquid film fragmentation. Visual observation verified that the liquid film and fragmentation on the hub are significantly reduced. This is consistent with the quantitative measurement of void fraction distribution by wire mesh conductivity sensor (WMS). The average void fraction at the outlet of the new swirler (1.3D above) is increased, especially in low gas flow rate and high fluid flow rate cases, and the maximum increasement is as high as 26.0% compared to the original arc-vane swirler. The results deepen our knowledge about the film structure near the outlet of swirler in vane-type separators and provide guide to the optimization of vanes.