CAREER: Extinction Phenomena in Turbulent Liquid Dual-Fuel Flames

高能量密度液体燃料的湍流燃烧是航空应用的核心。液体燃料-氢气混合燃料的双燃料运行已成为一个研究热点。在高度湍动的反应流中，复杂液体燃料的现代实验研究知识有限。主要的研究目标是研究高度湍流的液体燃料火焰中氢浓缩的基于消光的过程，并开发新的激光诊断工具来实现这些研究。教育活动的重点是在本科生和研究生课程中增加燃烧物理内容，并创建视觉演示活动。涵盖燃烧和能源科学主题的学习模块将基于本科生研究人员设计和建造的实验演示。这些演示设备可以移动到教室环境和外展活动中。学习模块将被开发用于在线分享，通过PBS WKAR进行电视转播，以及在YouTube上进行全球访问。主要研究目标是研究高雷诺数、湍流液体双燃料、富氢火焰在全球和局部尺度上的基于熄灭的过程。在给定不同的Le混合物和潜在的不均匀混合的情况下，将特别强调研究氢浓缩对火焰结构中局部消光的影响。这项研究将集中在主要预燃火焰的动力学和稀滴-喷雾火焰，每个火焰都具有独特的主导热物理性质和由于液滴、燃料蒸汽、湍流和火焰之间的相互作用而熄灭的机制。该实验计划的目的是(1)解决全球喷出瞬变和局部消光过程之间的耦合问题，(2)提出液体燃料火焰中CH/甲醛PLIF和瑞利散射测温的新诊断方法，以及(3)捕获火焰结构、温度、标量耗散和曲率的统计数据，这些统计数据可以通过验证质量的数据集纳入高级模拟和建模中。新开发的诊断策略将用于观察由于曲率和Le效应而产生的湍流-化学相互作用对火焰结构的消光影响。对这些流动中二维标量场的测量将提供关于温度、进度变量和标量耗散的联合PDF统计数据，这些统计数据尚未在实验中报告用于较重碳氢燃料。这些新工具的提供将使人们能够深入了解以前无法接触到的液体燃料燃烧制度。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Turbulent combustion of energy-dense, liquid fuels is at the core of aviation applications. Dual-fuel operation with liquid fuel – hydrogen blends have become a research point of interest. There is limited knowledge from modern experimental studies of complex liquid fuels in highly turbulent reacting flows. The overarching research goal is to investigate extinction-based processes in highly turbulent liquid-fueled flames with hydrogen enrichment and develop new laser diagnostic tools to enable these studies. Educational activities are focused on the addition of combustion physics content to undergraduate and graduate courses and the creation of visual demonstration activities. Learning modules covering combustion and energy science topics will be based on experimental demonstrations designed and built by undergraduate researchers. These demonstrator devices are transportable to classroom settings and outreach engagements. Learning modules will be developed for online sharing, televised delivery with PBS WKAR, and for global access on YouTube.The primary research goal is to investigate extinction-based processes during blowoff at global and local scales in high-Reynolds number, turbulent liquid dual-fuel, hydrogen enriched flames. Particular emphasis will be placed on studying hydrogen enrichment effects on local extinctions in flame structure given varying Le mixtures and potentially inhomogeneous mixing. This study will focus on the dynamics of primarily prevaporized flames in addition to dilute droplet-spray flames, which each have unique dominating thermophysical properties and extinction mechanisms due to interactions between droplets, fuel vapor, turbulence, and flame. The experimental program has been designed to (1) address aspects on coupling between global blowoff transients and local extinction processes, (2) advance new diagnostic methods for CH/formaldehyde PLIF and Rayleigh scattering thermometry in liquid fuel flames, and (3) to capture statistics on flame structure, temperature, scalar dissipation, and curvature that can be incorporated into advanced simulations and modelling via validation-quality datasets. Newly developed diagnostic strategies will be used to observe extinctions in flame structures influenced by turbulence-chemistry interactions due to curvature and Le effects. Measurement of 2-D scalar fields in these flows will provide joint PDF statistics on the temperature, progress variable, and scalar dissipation which has not been experimentally reported for heavier hydrocarbon fuels. The availability of these new tools will allow for insights into previously inaccessible regimes of liquid fuel combustionThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.