Preliminary Analysis of Swirl Effervescent Atomization Droplet Diameter Distribution

A swirl effervescent atomizer capable of producing fine droplets with relatively low injection pressures. A critical aspect of atomization is the resultant droplet diameter distribution, which portrays the efficiency of the atomization process. Dimensional analysis was conducted to identify the most significant parameters influencing the droplet diameter distribution. Three dimensionless numbers were selected considering their importance, which are the liquid Reynolds number, Re, the gas Reynolds number, and the swirl chamber length to discharge orifice diameter ratio. A test rig was fabricated to test the atomizer. Water acts as the working fluid, and air acts as the atomization assistance. The resultant spray images were captured using the shadowgraph technique. The images were analysed for droplet diameter measurement. The liquid Reynolds number and gas Reynolds number were found to have a significant impact on the droplet diameter distribution, particularly with an increase in the percentage of fine droplets. However, the dependence of the droplet diameter distribution on the geometrical ratio is less significant. This result is important for a preliminary understanding of the swirl effervescent atomization mechanics.