Characterization of high-pressure water-mist sprays: Experimental analysis of droplet size and dispersion

Popularity of water mist is increasing for a variety of applications within the broad areas of fire suppression and surface cooling. The present study has been focused on characterizing the solid-cone water-mist spray produced by a typical atomizer at high operative pressure (in the range 60–80 bar). To this end, an experimental campaign has been conducted, mainly employing optical techniques: drop-size and flux distribution, initial velocity and cone angle have been investigated to provide a quantitative description of atomization and dispersion.Most notably, a laser-diffraction-based instrument (Malvern Spraytec) has been used to evaluate drop size, while velocity field and spray-cone angle have been studied by Particle Image Velocimetry (PIV) technique. Appropriate measurement methodologies have been developed to the purpose. Moreover, a theoretical discussion based on inviscid-fluid assumption is presented and some relations have been evaluated as predictive of the considered parameters.