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

越来越多的发动机和发电系统采用基于喷雾的方法将燃料引入燃烧室。喷雾和喷雾燃烧涉及物理过程（如燃料汽化、燃料-空气混合）和化学过程（如点火、污染物形成），这两个过程都没有被完全理解。此外，汽化和混合为燃烧设定了初始条件，从而直接影响燃烧效率和排放。本研究的目的是研究燃料喷射的物理过程，特别是在燃料喷射到相对低温和低密度环境的情况下。这种情况是先进的发动机燃烧策略的特征，例如早期直接喷射，越来越多地用于提高效率和降低有害排放。研究将在一个设计有广泛光学通道的喷雾室中进行，在实验过程中，惰性气体将持续流动，以便在没有燃烧的复杂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蒸汽相的穿透、分散和湍流。这些数据将使用作为该项目的一部分而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，利用一台高速摄像机同时获得液相和气相信息。实验结果可能会导致改进和更灵活的模型的发展，这些模型可能会挑战关于燃料喷雾的传统智慧。该项目将通过为研究活动和代表人数不足的学生的研究生教育提供支持，对代表人数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教育，因为研究者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，从而有助于开发更清洁、更高效的燃烧装置。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.