Experimental study of gas jet-induced aero breakup of suspended bubbles

Abstract

Effervescent atomization technology has been widely used in industrial production, firefighting, and other fields due to its simple structure, high atomization quality, and low energy consumption. This is accomplished through the aerodynamic fragmentation of the bubble stream as it exits the nozzle in free space. Therefore, the process of breaking the bubbles is of great consequence in determining the initial atomization pattern of the effervescent atomizing nozzle. Insufficient fragmentation of the bubble stream may result in diminished spray stability and atomization quality. To elucidate the process by which bubbles begin to fragment and to optimize the effervescent atomization technique, this study employed image analysis to delineate the breaking dynamics of suspended bubbles in high-speed side airflow and identifies three distinct modes of bubble aero breakup under such airflow-varying conditions. Moreover, the study systematically investigated the effects of airflow velocity and bubble diameter on the aerodynamic breakup of bubbles, introducing a novel bubble deformation indicator to predict the likelihood of bubble breakup occurrence. The findings indicate that as the axial velocity of the gas jet increased, the mode of bubble aero breakup transitioned from bubble detachment to windward and leeward breakup. Furthermore, the degree of deformation of the windward surface is essential in determining whether the bubble will break. This research revealed the dynamics of bubble aero breakup and identified the influential factors under disturbance conditions, offering a theoretical basis and practical guidance for engineering applications and scientific research.