Extinction and reignition in a diffusion flame:: a direct numerical simulation study
Extinction and reignition in a diffusion flame:: a direct numerical simulation study
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DOI：
10.1017/s0022112004001004
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发表时间：
2004-11-10
影响因子：
3.7
通讯作者：
Pitsch, H
中科院分区：
文献类型：
--
作者：
Sripakagorn, P;Mitarai, S;Pitsch, H
本研究的目的是通过使用一步全局反应和忽略密度变化的各向同性衰减湍流中非预混燃烧的三维模拟，为熄灭和重燃的物理学提供一个窗口。燃料和氧化剂的非预混场是在紊流场中发展起来的。由于应变作用，标量耗散率开始增大，其波动在化学计量表面上产生消光区。在稍后的过程中，化学计量表面再次变得均匀热。除了使用欧拉数据外，本研究还应用了火焰元跟踪，并研究了化学计量表面上单个点（“火焰元”）的时间历史。研究的主要重点是讨论不同的重燃情景。本文确定了三种主要场景：独立小火焰场景，通过边缘（三重）火焰传播重新点燃，以及通过热邻居吞没重新点燃。研究结果揭示了不同场景在重燃过程中的作用，揭示了与每种场景相关的物理过程，并提供了每种场景的相对重燃频率。
The goal of this study is to provide a window into the physics of extinction and reignition via three-dimensional simulations of non-premixed combustion in isotropic decaying turbulence using one-step global reaction and neglecting density variations. Initially non-premixed fields of fuel and oxidant are developing in a turbulent field. Due to straining, the scalar dissipation rate is initially increasing and its fluctuations create extinguished regions on the stoichiometric surface. Later in the process, the stoichiometric surface again becomes uniformly hot. Besides using Eulerian data, this research applies flame element tracking and investigates the time history of individual points ('flame elements') along the stoichiometric surface. The main focus of the study is the discussion of the different scenarios of reignition. This paper identifies three major scenarios: independent flamelet scenario, reignition via edge (triple) flame propagation, and reignition through engulfment by a hot neighbourhood. The results give insight into the role different scenarios play in the reignition process, reveal the physical processes associated with each scenario, and provide the relative frequency of reignition for each scenario.