Multiscale analysis of turbulence-flame interaction in premixed flames
Multiscale analysis of turbulence-flame interaction in premixed flames
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DOI：
10.1016/j.proci.2016.07.111
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发表时间：
2017-01-01
影响因子：
3.4
通讯作者：
Chakraborty, N.
中科院分区：
文献类型：
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作者：
Doan, N. A. K.;Swaminathan, N.;Chakraborty, N.
采用直接数值模拟（DNS）的预混火焰的数据进行多尺度分析的湍流火焰相互作用。采用带通滤波方法，得到了不同尺度的湍流涡及其涡量场和应变率场。尺度为4L（Ω）的涡旋的最大伸展主应变率强烈地拉伸了尺度为L-omega的涡旋结构，这与非反应湍流中的行为相似。因此，燃烧不影响涡流拉伸机制的物理性质。研究了尺度为L-s的涡对总切向应变率的贡献。结果突出显示，大于层流火焰热厚度的两倍的涡流主要有助于火焰应变，并且对于湍流强度，小于2 δ（th）的涡流对总切向应变率的贡献小于10%，从u '/s（L）= 1。41到u '/s（L）= 11。25、在这里调查通过分析确定的截止尺度大于以前的主张，这一发现的亚网格尺度预混燃烧模型的影响进行了讨论。(C)2016年，燃烧研究所。由爱思唯尔公司出版
Multiscale analysis of turbulence-flame interaction is performed using direct numerical simulation (DNS) data of premixed flames. Bandpass filtering method is used to educe turbulent eddies of various sizes and their vorticity and strain rate fields. The vortical structures at a scale of L-omega are stretched strongly by the most extensional principal strain rate of eddies of scale 4L(omega), which is similar to the behaviour in non-reacting turbulence. Hence, combustion does not influence the physics of vortex stretching mechanism. The fractional contribution from eddies of size L-s to the total tangential strain rate is investigated. The results highlight that eddies larger than two times the laminar flame thermal thickness contributes predominantly to flame straining and eddies smaller than 2 delta(th) contributes less than 10% to the total tangential strain rate for turbulence intensities, from u'/s(L) = 1. 41 to u'/s(L) = 11. 25, investigated here. The cutoff scale identified through this analysis is larger than the previous propositions and the implication of this finding to subgrid scale premixed combustion modelling is discussed. (C) 2016 by The Combustion Institute. Published by Elsevier Inc.