Flame self-interactions in an open turbulent jet spray flame
Flame self-interactions in an open turbulent jet spray flame
复制标题
DOI：
10.1063/5.0039155
复制
发表时间：
2021-03-01
影响因子：
4.6
通讯作者：
Kurose, R.
中科院分区：
文献类型：
--
作者：
Malkeson, S. P.;Ahmed, U.;Kurose, R.
根据作者所知，首次对实验室燃烧器结构的开放式湍流射流火焰的三维直接数值模拟数据库进行了分析，以研究存在流动诱导剪切时的火焰自相互作用。FSI事件[即，未燃烧气体混合物袋（UBGP）、隧道形成物（TF）、隧道封闭物（TC）和已燃烧气体混合物袋（BGP）]已经在火焰的不同轴向位置处被识别。已经发现，湍流、液滴蒸发和化学之间的相互作用对火焰表面的拓扑性质有显著影响。接近射流出口，FSI事件被发现发生朝向燃烧气体侧的火焰，但进一步远离射流出口，有显着的FSI事件发生在火焰内，其中越来越富燃料，低达姆科勒数的条件发生。在这项研究中，FSI事件已被发现主要是TF和TC，这是与先前的分析湍流预混火焰和燃烧液滴载货混合物。然而，在这种情况下也观察到不可忽略的UBGP和BGP的出现。从这个分析得到的结果具有重要的影响，从建模的角度来看，火焰拓扑结构有显着的影响，火焰表面的性质，这反过来又会影响火焰表面的建模方法。因此，目前的分析结果可能需要考虑在湍流喷雾火焰的背景下，火焰表面为基础的关闭的发展。
A three-dimensional direct numerical simulation database of an open turbulent jet spray flame representing a laboratory-scale burner configuration has been analyzed to investigate flame self-interactions (FSIs) in the presence of flow induced shear, to the best of the authors' knowledge, for the first time. The FSI occurrences [i.e., unburned gas mixture pockets (UBGPs), tunnel formations (TFs), tunnel closures (TCs), and burned gas mixture pockets (BGPs)] have been identified across the flame at different axial locations. It has been found that the interplays between turbulence, droplet evaporation, and chemistry have a significant influence on the topological nature of the flame surface. Close to the jet exit, the FSI events are found to occur toward the burned gas side of the flame, but moving further away from the jet exit, there are significant occurrences of FSI events within the flame where increasingly fuel-rich, low Damkohler number conditions occur. In this study, the FSI events have been found to be predominantly TFs and TCs, which is consistent with previous analyses of turbulent premixed flames and combustion of droplet-laden mixtures. However, non-negligible occurrences of UBGPs and BGPs are also observed in this case. The results obtained from this analysis have important implications from a modeling perspective where flame topologies have a significant influence on the nature of the flame surface, which will, in turn, affect the flame-surface based modeling approaches. Accordingly, the findings of the current analysis may need to be accounted for during the development of flame surface-based closures in the context of turbulent spray flames.