Experimental study on electrohydrodynamics (EHD) spraying of ethanol with double-capillary

Abstract

This paper presents a visualization study on electrohydrodynamics (EHD) spraying of ethanol with double-capillary. The tilted dripping, spindle, pulsated-jet, whipping-jet, tilted straight jet and multi-jet modes are reported through off-line analyzing images captured by microscopy with photographingfrequency of 104Hz. The time-resolved evolution of each spraying mode has been thoroughly analyzed in a complete cycle. The repetition frequency, drops size and the angle between the direction of drop/jet movement and nozzle axis under non-continuous spraying modes have also been presented and discussed. The drop size is evidently associated with spraying mode and is larger for dripping and spindle modes, while smaller for jet modes. The drop size distribution follows the universal scaling laws in cone-jet mode. The repetition frequency increases with applied voltage increased and have a sharp jump with transition of dripping into spindle mode. The peak repetition frequency isrelatedtothe flow rate in present study. The angle strongly depends on repulsive force or electrical strength. For dripping and spindle modes, the angle increases with an increase in applied voltage and flow rate. In each complete cycle, the angle decreases as drop falling down. There are larger variations in angle for different modes because of electrical and gravity forces alternating.