Structure of a spatially developing turbulent lean methane–air Bunsen flame
Structure of a spatially developing turbulent lean methane–air Bunsen flame
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DOI：
10.1016/j.proci.2006.08.025
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发表时间：
2007
影响因子：
3.1
通讯作者：
R. Sankaran;E. Hawkes;Jacqueline H. Chen;T. Lu;C. Law
中科院分区：
文献类型：
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作者：
R. Sankaran;E. Hawkes;Jacqueline H. Chen;T. Lu;C. Law
使用新的还原甲烷-空气机制对三维空间发展的湍流狭缝燃烧器本生火焰进行了直接数值模拟。该机制源自有向关系图理论、敏感性分析和计算奇异扰动对 GRI-1.2 详细机制的顺序应用，是非刚性的，并且适合 DNS 的贫乏条件。模拟进行了三个流动时间，足够长以实现统计平稳性。湍流参数的选择使得燃烧发生在预混合燃烧的薄反应区状态中。分析数据以研究湍流对预热区和反应区结构的可能影响。结果表明，基于进度变量梯度的湍流火焰的平均厚度大于相应的层流火焰。通过厚度的条件方法并通过检查火焰厚度演变的平衡方程来量化流动应变和火焰前锋曲率对平均火焰厚度的影响。最后，与层流反应速率曲线相比的关键物质的条件平均反应速率表明，放热层没有显着的扰动。
Direct numerical simulation of a three-dimensional spatially developing turbulent slot-burner Bunsen flame has been performed with a new reduced methane–air mechanism. The mechanism, derived from sequential application of directed relation graph theory, sensitivity analysis and computational singular perturbation over the GRI-1.2 detailed mechanism is non-stiff and tailored to the lean conditions of the DNS. The simulation is performed for three flow through times, long enough to achieve statistical stationarity. The turbulence parameters have been chosen such that the combustion occurs in the thin reaction zones regime of premixed combustion. The data is analyzed to study possible influences of turbulence on the structure of the preheat and reaction zones. The results show that the mean thickness of the turbulent flame, based on progress variable gradient, is greater than the corresponding laminar flame. The effects of flow straining and flame front curvature on the mean flame thickness are quantified through conditional means of the thickness and by examining the balance equation for the evolution of the flame thickness. Finally, conditional mean reaction rate of key species compared to the laminar reaction rate profiles show that there is no significant perturbation of the heat release layer.