A Droplet Tagging Method to Investigate Diesel Spray

Spatial profiles of the droplet velocities and sizes from a steady state ‘Diesel type’ spray exhausting into open atmosphere have been performed using a Phase Doppler Anemometer. An analysis of the size selective behavior of the droplets has been carried out by dividing the droplets into five size classes, and the comparisons between the droplets behavior and the continuous phase behavior could provide interesting topics. But the measurements of the gaseous phase velocity in and outside such a spray are limited. A technique taking into account these velocities has then been developed using a droplet tagging method. Tagged droplets with a fluorescent dye, while passing through the two-components LDA probe volume, emit light at the fluorescent wavelength, plus the Mie scattered light. LDA signal discrimination is then based on a spectral filtering of the scattered intensifies, Even if its application has not yet been performed on such a spray, the technique has shown some interesting potentialities in studying the mixing of two flows and thus shows promise in studying the complex aerodynamic behavior of a Diesel spray by considering the air entrainment into the spray as the mixing of two flows. The goal of this paper is to present the potentialities of this method and its limits.