横流作用下空心锥形喷雾液滴群的扩散与蒸发机理研究

The mixing of hollow cone spray in crossflow is an important method to intensify the heat and mass transfer between liquid and gasflow. During the mixing process, the interaction between the spray and the crossflow generates a series of complex vortex structures, which in turn exert significant influences on the droplet dispersion and evaporation, and eventually make the mixing highly nonlinearity and complex phases distribution characteristics. In addition, the gaseous vortices and the droplet temperature in the mixing flow field are still hard to measure, which also impedes the understandings of the interaction mechanisms between the spray and the crossflow. In this project, we will develop new methods of the synchronous measurement of the gas and droplet velocities and the temperature measurement of spray droplets. This will make us to precisely capture the features of the vortices and the characteristics of the droplet dispersion and evaporation. Based on these results and the theoretical analytical approaches, the formation and evolution of the large-scale vortices will be obtained and the influence mechanisms of them on the droplet dispersion and evaporation will be clarified. On this basis, the interaction mechanisms between the hollow cone spray and the crossflow will be illustrated and the relevant prediction models will also be developed. The measurement methods for parameters in two-phase flow proposed here will provide technical support in studying multiphase flow in other fields, and the research findings will provide theoretical support for the application of the mixing of hollow cone spray in crossflow in the new types of super-speed thermal power propulsion systems and other relevant mixing systems.

空心锥形喷雾与横流的掺混是一种强化气液相间能质输运的重要方式。喷雾与横流相互作用诱发流场出现复杂旋涡结构，气液相间强耦合使掺混过程呈现非定常与复杂相分布特征。目前对流场气液两相速度和液滴群温度仍缺乏准确有效的测试技术，制约了对横流作用下喷雾液滴群扩散与蒸发过程的机理认识和相关理论模型的发展。本项目拟基于分子标记技术发展适用于掺混过程气液两相速度同步测量和液滴群温度场测量的新方法，实现流场气相涡结构和液滴群扩散与蒸发行为的精确捕捉。发展数值模拟方法并结合理论分析，查清掺混流场中气相大尺度涡的结构特征、形成原因及演变规律；揭示大尺度涡对雾化液滴群扩散与蒸发过程的作用机理；建立描述喷雾液滴群扩散与蒸发主要行为特征的理论预测模型。本项目发展的气液两相流场参数测试方法将为多相流实验研究提供技术支撑，同时研究成果将为发展新型高速/超高速热动力推进系统以及其他领域中的高效射流掺混组织技术提供理论指导。

空心锥形喷雾与横流的掺混是一种强化气液相间能质输运的重要方式，在诸多类新型热动力系统中有重要应用需求。由于对两相流场中气液两相速度和液滴温度等仍缺乏准确有效的测试技术，以及高精度数值模拟方法不成熟，使得高温、受限空间等复杂条件下气液两相掺混机理认识不清，制约了相关热动力系统中气液掺混组织技术的开发。本项目通过机理实验、理论建模和数值模拟相结合的研究方法，系统研究了横向气流与空心锥形喷雾作用下气液两相流的关键基础科学问题，创新提出了高温射流气液掺混过程的机理模化方法实现中常温模化实验研究，发明了高速云雾气液两相流场气相温度、局部液滴分布/液相水含量等测量新方法，开发了基于分子荧光/磷光测量气流速度和液滴温度等非接触测量技术，构建了空心锥形喷雾过程高精度数值模拟方法、破碎距离等预测模型和横流作用下雾化液滴群的扩散蒸发特性预测模型，查清了空心锥形喷雾与横流掺混过程中大尺度涡的形成原因、结构特征与演变规律，阐明了掺混过程中湍流涡作用下喷雾液滴的扩散机理与蒸发特性，掌握了横流作用下空心锥形喷雾液滴群扩散与蒸发过程规律和强化组织方法。本项目发展的气液两相流场参数测试方法为多相流实验研究提供了技术支撑，同时研究成果得到了工程应用，为发展新型热动力推进系统以及相关领域中的高效射流掺混组织技术提供了理论指导。