The Effects of Heat Release on the Flow Structure of Planar Hydrogen Diffusion Flames

摘要-- CTS-9319136 CLEMENS 热释放对湍流结构和混合过程的作用尚未完全确定。 了解这一现象对我们处理湍流反应流的能力是非常重要的。 该建议提出了一个研究计划，如果成功，将有助于重要的知识湍流燃烧领域的实验确定热释放的影响，测量非预混氢/空气火焰使用平面狭缝燃烧器。 所提出的工作的目的是记录混合限制条件下的高水平的热释放的影响，对平面射流火焰的大尺度湍流结构。 拟议的努力是在桑迪亚所做的工作的延伸，而PI是一个博士后研究员。 本文研究了氢气/空气圆射流火焰的近场结构。 激光诱导荧光（LIF）被用来可视化的反应区的OH激发和燃料的种子丙酮的激发被标记。 在反应的情况下，观察到的流场的相当大的修改相比，非反应的情况下，湍流出现显着分层和混合层的增长率大大降低，热反应区出现稳定的局部湍流波动，导致独立的反应和湍流区域。为了简化对这些实验的解释，PI提出了一系列实验，其中将使用更简单的几何剪切流（由平面混合层提供），以希望获得更清晰的证据，证明高水平的热释放对流动的修改。 一个平面射流喷嘴流动设施连同流动可视化技术，包括OH和丙酮PLIF和平面米氏散射的种子陶瓷颗粒将用于这项拟议的调查。 将对冷流和热流进行比较。 这项研究的一个主要目标是比较燃烧射流的大尺度结构与非燃烧射流的结构。 这项研究工作可能会导致重要的贡献，在理解湍流反应流。

ABSTRACT -- CTS-9319136 CLEMENS The role of heat release on the structure of turbulence and the mixing process has not been fully established. The understanding of this phenomenon is very important to our capability of dealing with turbulent reacting flows. This proposal presents a research plan, that if successful, will contribute important knowledge to the field of turbulent combustion by experimentally determining heat release effects, measured on non-premixed Hydrogen/Air flames using a planar slot burner. The objective of the proposed work is to document the influence of high levels of heat release under mixing limited conditions, on the large-scale turbulent structure of planar jet flames. The proposed effort is an extension of work done at Sandia while the PI was a post doctoral fellow. In this study, the near field structure of Hydrogen/Air round jet flames was investigated. Laser Induced Fluorescence (LIF) was used to visualize the reaction zone by excitation of OH and the fuel was marked by excitation of seeded acetone. Considerable modification of the flow field in the reacting case was observed as compared to the non-reacting case; turbulence appeared to be significantly laminarized and the growth rate of the mixing layer greatly reduced; the hot reaction zone appeared to stabilize the local turbulent fluctuations, resulting in an independence of the reacting and turbulent regions. In order to simplify the interpretation of these experiments, the PI has proposed a series of experiments in which a simpler geometry shear flow (provided by a planar mixing layer) will be used to hopefully yield clearer evidence for the modifications to the flow by high levels of heat release. A planar jet nozzle flow facility together with flow visualization techniques including OH and acetone PLIF and planar Mie scattering of seeded ceramic particles will be used in this proposed investigation. Comparisons of cold and hot flows will be made. A major goal of the study will be to compare the large-scale structure of burning jets to the structure of their non-burning counterparts. This research effort could lead to important contributions in the understanding of turbulent reacting flows.