The dynamic behaviour and structures of laminar counterflow diffusion methane flames under oscillatory strain rates are investigated based on both detailed and reduced chemistry. It is known both from experiment and numerical studies that flame can deviate from its quasi-steady manner for high frequencies, which makes the well-known steady laminar flamelet model questionable. In this work, the Reaction-diffusion manifolds (REDIM) concept for simplified chemistry is applied to study the laminar counterflow diffusion flames with oscillating strain rates. In the construction of REDIM, one needs little knowledge of the studied system, and the REDIM reduced chemistry can cover both stable and unstable (extinction) regimes of the studied system. It is shown that the REDIM can capture both the steady and unsteady behaviours of the flame structures even for high frequencies, where the standard laminar steady flamelet approach is not appropriate.

中文翻译：

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REDIM 用于模拟具有振荡应变率的逆流扩散火焰的化学还原

层流逆流扩散甲烷火焰在振荡应变率下的动态行为和结构基于详细化学和简化化学研究。从实验和数值研究中都知道，对于高频，火焰可能会偏离其准稳态方式，这使得众所周知的稳态层流小火焰模型存在问题。在这项工作中，用于简化化学的反应扩散歧管 (REDIM) 概念被应用于研究具有振荡应变率的层流逆流扩散火焰。在 REDIM 的构建中，几乎不需要对所研究系统的了解，REDIM 还原化学可以涵盖所研究系统的稳定和不稳定（消光）状态。