Multiple conditioned analysis of the turbulent stratified flame A
Multiple conditioned analysis of the turbulent stratified flame A
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DOI：
10.1016/j.proci.2016.08.070
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
Thabo Stahler;D. Geyer;G. Magnotti;Philipp Trunk;Matthew J. Dunn;R. Barlow;A. Dreizler
中科院分区：
文献类型：
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作者：
Thabo Stahler;D. Geyer;G. Magnotti;Philipp Trunk;Matthew J. Dunn;R. Barlow;A. Dreizler
为了研究湍流条件下分层对贫油预混燃烧的影响，对达姆施塔特分层燃烧器的TSFA火焰进行了实验研究。通过1D Raman-Rayleigh测量空间高分辨率的主要物质浓度和温度。从线数据的温度梯度校正到火焰前缘法线的交叉平面瑞利成像的装置。基于分层燃烧相关的多个标准的调节应用于大型数据集，并允许分析分层对火焰结构的影响。调节标准是局部当量比（ε = 0.75）、局部热进程变量（c= 0.54）、分层水平（当量比中的瞬时火焰法向梯度）和一维探头体积上的温差，以确保包括火焰前缘。对流平均量，如火焰正常坐标系中的温度分布，当量比，H2质量分数，和温度梯度参数化的局部当量比梯度，以了解分层对火焰结构的影响。在该背支撑配置中的温度分布在反应物侧上比在产物侧上受到分层的影响更大。与此相反，当量比以及氢的质量分数被发现是敏感的分层上的产品侧，以及在反应物。通过提高当量比梯度，甚至在反应区中也改变了轮廓，这与在剑桥/桑迪亚构型中获得的结果相反。这一发现表明了湍流对薄反应区区域分层燃烧的影响，例如，达姆施塔特与剑桥/桑迪亚构型的Karlowitz和Damköhler数的差异就表明了这一点。
To explore the effect of stratification on lean premixed combustion in a turbulent flow, an experimental investigation on the TSFA flame of the Darmstadt stratified burner is conducted. Spatially highly resolved major species concentrations and temperature are measured by 1D Raman–Rayleigh. Temperature gradients from line data are corrected to the flame front normal by the means of Crossed Planar Rayleigh Imaging. A conditioning based on multiple criteria relevant for stratified combustion is applied to the large dataset and allows to analyze the impact of stratification on the flame structure. Conditioning criteria are the local equivalence ratio (ϕ = 0.75), the local thermal progress variable (c= 0.54), the stratification level (instantaneous flame-normal gradient in equivalence ratio), and a temperature difference over the 1D probe volume, ensuring the flame front is included. Conditionally averaged quantities such as temperature profiles in the flame-normal coordinate system, equivalence ratio, H2mass fractions, and temperature gradients are parameterized on the local equivalence ratio gradient in order to understand the impact of stratification on the flame structure. The temperature profiles in this back-supported configuration are more affected on the reactant side than on the product side by stratification. In contrast to that, equivalence ratios as well as mass fractions of hydrogen are found to be sensitive to stratification on the product side as well as in the reactants. Profiles are altered even in the reaction zone by enhancing the equivalence ratio gradients, which is in contrast to results obtained in the Cambridge/Sandia configuration. This finding indicates the influence of turbulence on stratified combustion in the thin-reaction-zone regime, as characterized for instance by the difference in Karlowitz and Damköhler numbers for the Darmstadt versus the Cambridge/Sandia configuration.