Experimental study on flashing spray characteristics of pressure swirl nozzle with ethanol solution

Abstract Flashing spray has the potential to enhance the performance of aero-engine combustor, compared with conventional spray. In this study, the kerosene was replaced by ethanol solution, the influence of flashing degree of ethanol on spray profile, velocity distribution and droplet size distribution was investigated based on the ratio of the ambient pressure to saturation pressure using the particle image velocity and laser particle size analyzer. Results indicated that when the ratio of ambient pressure to saturation pressure was reduced, the micro-explosion effect was intensified, spray cone angle was first increased and then decreased, and the radial velocity peak and velocity gradient were improved. The downtrend of sauter mean diameter became faster and it was dominated by the ratio of ambient pressure to saturation pressure, the cumulative distribution ratio and frequency distribution were changed, small droplets produced by the micro-explosion effect mainly existed in 16% of the total droplet volume. Moreover, the formation mechanism of recirculation zone upstream of the spray field was proposed, and the difference of formation and breakup of liquid sheet between conventional spray and flashing spray was analyzed. These results provide insightful information for understanding flashing spray characteristics with pressure swirl nozzle.