减少汽油直喷发动机冷氛围下闪沸喷雾撞壁附着油膜质量是进一步提升燃烧排放性能的瓶颈问题。本项目提出应用液相复合激光诱导荧光油膜测试新方法，结合双色粒子成像测速法等光学诊断技术，系统开展内燃机冷氛围下闪沸喷雾运动和撞壁形成油膜的过程和机理研究。通过获得静态环境和动态环境下闪沸喷雾宏观结构和微观特征、液滴速度和粒径分布、瞬态撞壁油膜厚度和温度分布等关键参数，综合分析喷雾坍塌和内燃机结构气流作用下的闪沸喷雾形态变化、近壁面准撞壁液滴动力学状况与撞壁油膜生成发展过程三者之间的作用机理；揭示内燃机冷氛围下系统动力学特性和热力学特性对闪沸喷雾撞壁油膜生成、发展和蒸发过程的影响规律，完善闪沸喷雾撞壁和油膜发展机理模型，并探索减少闪沸喷雾撞壁油膜质量的技术途径和控制策略。本研究对深入认识闪沸喷雾撞壁油膜生成机理具有重要理论意义，对寻求高效清洁的闪沸喷雾燃烧的实现途径具有重要指导价值。

To reduce the adhered fuel mass caused by flash boiling spray impingement for gasoline direct injection engines in cold environments is the bottleneck in further improving the thermal efficiency and reducing emission from flash boiling combustions. The current investigation will use a novel liquid laser-induced exciplex fluorescence for fuel film measurements, as well as other optical diagnostic methods such as two-color particle image velocimetry, to carry out systematically studies on the fundamental processes and mechanisms of flash boiling spray propagation and impingement in cold environments. Via obtaining critical parameters such as macroscopic and microscopic features of flash boiling sprays, droplet sizes and velocities, as well as thickness and temperature spatial distribution of the fuel film in both quiescent and dynamic environments, this project will thoroughly analyze the connections among spray structural variation under the influence of spray collapse and structured engine intake flows, the dynamics of pre-impingement droplets, and the generation and development of impingement films. With such efforts, this research aims to illustrate the impact mechanisms of kinematic and thermodynamic characteristics on the formation, development, and evaporation of the impingement films under cold engine environments. Thus, the mechanisms and models of flash boiling impingement and film development can be improved. Finally, this study will explore technical paths and control strategies in reducing flash boiling impingement fuel mass. This investigation has significant theoretical values in deepening the understandings of flash boiling film generation mechanisms, as well as remarkable instructive values in the efforts of seeking high-efficiency and clean flash boiling combustion approaches.