Vortex and its implication on separation performance in an electro-swirling coupling device

Abstract

ABSTRACT An electro-swirling coupling device coupled with electric field and centrifugation can achieve demulsification and dewatering of emulsion efficiently and economically. But, the vortex structure and its implication on separation performance under the coupling condition are unclear. Accordingly, a vortex analysis for the coupling separator was conducted numerically, and the effect of eccentricity on the efficiency was investigated. The results show that the iso-vortex surface is twisted and fluctuates. And there is a vibrational radial deviation between the vortex core and central axis, and increasing inlet velocity and voltage amplitude can increase the radial deviation of the vortex at the z-coordinate range from 250 to 550 mm. Furthermore, the underlying reason for the increase in vortex eccentricity is different where the electric coalescence is for the increase in voltage amplitude and the fluid kinetic energy is for the increase in inlet velocity. Moreover, the separation efficiency increases with the increase in vortex eccentricity at the case that the coalescence is dominant, but the separation efficiency gradually decreases with the increase in breakage rate and the droplet breakup is dominant.