Isolating effects of Darrieus–Landau instability on the morphology and propagation of turbulent premixed flames
Isolating effects of Darrieus–Landau instability on the morphology and propagation of turbulent premixed flames
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Darrieus-Landau 不稳定性对湍流预混火焰形态和传播的隔离效应
DOI：
10.1017/jfm.2022.180
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发表时间：
2022
影响因子：
3.7
通讯作者：
Matalon, Moshe
中科院分区：
文献类型：
--
作者：
Patyal, Advitya;Matalon, Moshe
这项工作的目的是提供对控制火焰-湍流相互作用机制的物理洞察，并探索无处不在的Darrieus-Landau不稳定性对传播的影响。它基于预混火焰的流体力学理论，认为火焰厚度比所有其他流体力学长度尺度都要小得多。在这个渐近极限下，火焰被限制在一个表面上，而火焰区内发生的扩散和反应过程由两个参数解释：未燃密度比和马克斯坦长度。健壮模型没有现象学和湍流模型假设，使火焰和流体流动之间的相互作用变得透明，并允许在改变湍流强度和混合物性质的同时检查火焰和流动特性的趋势。在这项研究中，它被用来检查由于湍流和不稳定的相互交织的影响而导致的火焰表面的形态变化，如火焰前沿的局部位移和曲率、火焰表面的皱折程度和整体火焰刷子厚度。它还提供了对湍流火焰速度及其对平均火焰曲率和所经历的流体动力应变的依赖关系的直接评估。还讨论了火焰对流动的影响，考察了拟能和标量梯度产生/破坏的各种机制，燃烧气体中产生的各向异性程度，以及火焰以外的涡旋运动的重组。
The objective of this work is to provide physical insight into the mechanisms governing flame–turbulence interactions and explore the impact of the ubiquitous Darrieus–Landau instability on the propagation. It is based on the hydrodynamic theory of premixed flames that considers the flame thickness much smaller than all other fluidynamical length scales. In this asymptotic limit, the flame is thus confined to a surface whilst the diffusion and reaction processes occurring inside the flame zone are accounted for by two parameters: the unburned-to-burned density ratio and the Markstein length. The robust model, which is free of phenomenology and turbulence modelling assumptions, makes transparent the mutual interactions between the flame and the fluid flow, and permits examining trends in flame and flow characteristics while varying the turbulence intensity and mixture properties. It is used in this study to examine the morphological changes of the flame surface that result from the intertwined effects of the turbulence and instability, as demonstrated by the local displacement and curvature of the flame front, the extent of wrinkling and folding of the flame surface, and the overall flame brush thickness. It also provides a direct evaluation of the turbulent flame speed and its dependence on the mean flame curvature and on the hydrodynamic strain that it experiences. Also discussed are the effects of the flame on the flow by examining the various mechanisms of enstrophy and scalar gradient production/destruction, the degree of anisotropy created in the burned gas, and the restructuring of the vortical motion beyond the flame.
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影响因子：
1.3
作者：
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影响因子：
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作者：
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DOI：
--
发表时间：
1992
期刊：
影响因子：
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作者：
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通讯作者：
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DOI：
--
发表时间：
2018
期刊：
影响因子：
--
作者：
A. Herbert;H. Kosaka;B. Böhm;A. Dreizler;N. Chakraborty;Papapostolou;H. Im;J. Hasslberger;M. Klein
通讯作者：
M. Klein