Experimental study on liquid spray and small droplet formation in ethanol-oil system in a DC electric field

A detailed experimental study on the evolution process of charged liquid deformation and breakup in another immiscible liquid from a capillary channel was conducted at micro-scale. By means of high-speed microscopy technique, various liquid spray modes and droplet formation processes were illustrated in detail at different flow rates and voltages. The effects of Reynolds (Re) and electric Bond (BoE) number on droplet size distribution were analyzed. It was found that droplet sizes rose with increasing Re while declined with increasing BoE. The experimental results show that electric field could promote interfacial area through decreasing interfacial tension to augment mass transfer between immiscible liquids at low flow rates. Besides, liquid spray experienced drip, deformation, breakup and jet modes with the increase of flow rate and electric potential. A critical Re of 170 was obtained beyond which electric field had little effect on liquid dynamic behaviors.