Relationships for maximum flame surface density and brush thickness through conditional analysis in turbulent premixed combustion
Relationships for maximum flame surface density and brush thickness through conditional analysis in turbulent premixed combustion
复制标题
通过条件分析湍流预混燃烧中最大火焰表面密度与刷厚度的关系
DOI：
10.1063/1.4816289
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发表时间：
2013
影响因子：
4.6
通讯作者：
Dongkyu Lee
中科院分区：
文献类型：
--
作者：
K. Huh;Jaesung Kwon;Dongkyu Lee
在高丹科勒数 (Da) 湍流预混燃烧中，根据反应进程变量 c 及其连续高阶导数 Σf′（或 −∂c/∂n）和 ∂2c/∂n2，引入了一种新的条件平均方法。 c 在空间中是连续且可微的，因此可以为有限厚度的小火焰以及无限薄的小火焰定义条件平均值。利用平均反应进度变量 c 和火焰表面密度 (FSD) Σf 的相应条件系数项导出一组耦合的传输方程。所有成分项的统计数据与之前的结果一致，并且显示出相同的定性趋势，而与新平均实践的压缩性无关。结果表明，最大 FSD Σmax 出现在火焰刷中满足关系 ∇2c¯+⟨∇·n⟩fΣf=0 的位置。在恒定切向应变率和平均曲率线性变化的假设下，导出了 Σmax 的解析表达式...
A new conditional averaging method is introduced in terms of the reaction progress variable, c, and its derivatives of successively higher orders, Σf′ (or −∂c/∂n) and ∂2c/∂n2, in high Damkohler number (Da) turbulent premixed combustion. c is continuous and differentiable in space so that conditional averages may be defined for flamelets of finite thicknesses as well as for infinitesimally thin flamelets. A coupled set of transport equations are derived with corresponding conditional coefficient terms for mean reaction progress variable, c¯, and flame surface density (FSD), Σf. Statistics for all component terms are consistent with previous results and show the same qualitative trends irrespective of compressibility by the new averaging practice. It is shown that the maximum FSD, Σmax, occurs at the location where the relationship, ∇2c¯+⟨∇·n⟩fΣf=0, holds in a flame brush. An analytical expression is derived for Σmax under the assumption of constant tangential strain rate and linear variation of mean curvat...