Study on the micro-explosion mechanism and influencing factors of oil water mixed fuel

In this study, the mechanism of micro-explosion/puffing of diesel-water and tail oil-water single droplet during evaporation was investigated, and the influence of temperature, water content, eccentricity, and their interaction on fragmentation time was analyzed. Separate single droplets into composite droplets and mixed droplets based on different nucleation methods. During the evaporation process of a single droplet, it underwent nucleation, bubble generation and growth, and fragmentation. The fragmentation modes of composite droplets and mixed droplets are manifested as micro-explosion and puffing. Specifically, the micro-explosion of mixed droplets can be divided into strong micro-explosion and weak micro-explosion. The occurrence of weak micro-explosion can be attributed to the following reasons: insufficient development of water(bubbles) near the surface leading to premature ejection, and preferential bubble growth near the surface impeding internal bubble expansion. In addition, temperature and water content had a dual effect on the micro-explosion characteristics of diesel-water droplets, and higher temperature and water content were conducive to the occurrence of micro-explosion in tail oil-water droplets. Temperature had the least effect on fragmentation time, followed by water eccentricity, and water content had the most significant impact. And the interaction between water content and eccentricity substantially affected fragmentation time, equating to the minimum distance from the water to the outer surface of the fuel droplet.