04 O 01 The electrohydrodynamics of electrified conical menisci

Electrostatic atomization of liquids has become a hot research area since the new and promising characteristics of the resulting spray have been brought to light, namely its fairly monodisperse size distribution, and its small and controllable droplet size. In the present work, using perturbation techniques and matched asymptotic analysis (Van Dyke, 1964; Kevorkian and Cole, 1980) based on a small parameter¹ 1 the ratio of the free charges' relaxation time to the residence time of fluid particles at the entrance of the microjet, Taylor's electrostatic theory for electrified liquid cones (Taylor, 1964) has been extended in order to take into account liquid and charge emissions in the form of a capillary microjet. Our results show analytically for the first time the droplet size, its charge, and the emmited current as functions of the liquid properties (essentially the electric conductivity, surface tension, and density) and the injected flow rate. This allows for a serious approaching to the real design for an entirely new fuel injection device generation.