Electrically insulating (dielectric) charged sprays have been experimentally investigated for commercial Diesel fuel using a charge injection atomizer with a copper electrode. Application of the dual-angle imaging technique has allowed, for the first time, a detailed characterization of the primary atomization zone of electrified sprays. The paper first presents the global structure including spray cone angle and the onset of spray dispersion, showing agreement with previous work. This is followed by new quantitative information on (i) liquid jet tip breakup location, (ii) initial size of non-spherical droplets generated from the jet tip and (iii) the velocity of produced droplets relative to that of liquid jet tip. Global images of spray structure are collected using a CCD camera while microscopic information is quantified using a dual-angle particle tracking velocimetry technique developed previously by the authors [1,2]. In agreement with previous work, the charge creates electrostatic repulsion between the surface and the tip of the liquid jet and this significantly affects the cone angle and breakup length. Findings on the relative velocity of atomized droplets to that of the liquid jet tip demonstrate an effect of the initial electrostatic charge present on the liquid jet surface on the subsequent velocity of generated droplets. The applied voltage significantly affects the relative position of break-up to dispersion onset. However, for the charge levels examined here, a minimal effect of charge on droplet size is noted.
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