EAGER: High-Speed Imaging Studies of Fuel-Spray Physics for Low-Temperature and Low-Density Ambient Conditions

发动机和发电系统越来越多地采用基于喷雾的方法将燃料引入燃烧室。喷雾和喷雾燃烧既涉及物理过程(如燃料蒸发、燃料-空气混合)，也涉及化学过程(如点火、污染物形成)，这两个过程都不是完全了解的。此外，汽化和混合设定了燃烧的初始条件，因此直接影响燃烧效率和排放。这项研究的目的是调查燃料喷洒所涉及的物理过程，特别是在燃料被喷洒到相对低温和低密度环境中的条件下。这样的条件是先进的发动机燃烧策略的特点，例如早期直接喷射，这些策略正越来越多地被用于提高效率和降低有害排放。研究将在喷雾室中进行，喷雾室设计有广泛的光学通道，在实验期间惰性气体将连续通过喷雾室，以便在没有复杂燃烧影响的情况下进行喷雾物理的基础研究。研究将集中在燃料喷雾的液体和汽相的渗透、扩散和湍流。这些数据将使用作为该项目一部分开发的新型高速成像技术来寻找。研究人员将尝试开发一种技术，使用单一的高速摄像机同时获取液体和气相信息。实验结果可能导致改进和更灵活的模型的开发，这些模型可能会挑战关于燃油喷洒的传统智慧。该项目将通过为代表性不足的学生的研究活动和研究生教育提供支持，对代表性不足的群体的参与产生直接和切实的影响。此外，该项目将有利于阿拉巴马大学机械工程系的本科生教育，因为研究人员将把研究的主题和结果纳入现有内燃机课程的讲座和实验室部分。更广泛地说，这项工作将有助于改进预测喷雾和燃烧模型，这反过来将有助于开发更清洁和更高效的燃烧设备。因此，这项研究有可能影响这个国家的能源安全和能源独立。

Increasingly, engines and power-generation systems are employing spray-based methods to introduce fuel into the combustion chamber. Sprays and spray combustion involve both physical processes (e.g., fuel vaporization, fuel-air mixing) and chemical processes (e.g., ignition, pollutant formation), neither of which are fully understood. In addition, vaporization and mixing set the initial conditions for combustion, and thus directly influence combustion efficiency and emissions. The purpose of this research is to investigate the physical processes involved in fuel sprays, particularly for conditions where fuel is sprayed into relatively low-temperature and low-density surroundings. Such conditions are characteristic of advanced engine combustion strategies, such as early direct-injection, which are increasingly being used to enhance efficiency and lower unwanted emissions. Research will be conducted in a spray chamber designed with extensive optical access, and through which an inert gas will flow continuously during experiments to allow fundamental studies of spray physics in the absence of the complicating effects of combustion. Studies will focus on penetration, dispersion, and turbulence of both the liquid and vapor phases of fuel sprays. These data will be sought using novel high-speed imaging techniques that will be developed as part of this project. The investigator will attempt to develop a technique to obtain both liquid- and vapor-phase information simultaneously using a single high-speed camera. Experimental results could lead to development of improved and more-flexible models that are likely to challenge conventional wisdom about fuel sprays.This project will have a direct and tangible effect on participation from underrepresented groups by providing support for the research activities and graduate education of an underrepresented student. In addition, the project will benefit undergraduate education in the Mechanical Engineering Department at The University of Alabama, as the investigator will incorporate the subject matter and results of the research into both the lecture and laboratory portions of an existing course in combustion engines. More broadly, the work will contribute to improvement of predictive spray and combustion models, which in turn will contribute to the development of cleaner and more-efficient combustion devices. This research, therefore, has the potential to impact the energy security and energy independence of this nation.