A Direct Numerical Simulation (DNS) study of statistically one-dimensional and planar, lean complex-chemistry hydrogen-air flames characterized by a low Lewis number $Le$ and three different Karlovitz numbers$Ka$ ranging from 3 to 33 is performed, with the same complex-chemistry flames being also simulated by setting molecular diffusivities of all species equal to the heat diffusivity of the mixture. The simulations predict a significant increase in a ratio of turbulent burning velocity to the laminar flame speed in the former ($Le<1$) flames when compared to the latter (equidiffusive) flames. Extreme points characterized by the peak (over the computational domain) Fuel Consumption Rate (FCR) or Heat Release Rate (HRR) are found at each instant. In the equidiffusive flames, such extreme FCR and HRR are close to their peak values in the unperturbed laminar flame. If $Le$ is low, the former rates are significantly higher than the latter ones due to an increase in the local temperature, equivalence ratio, and radical mass fractions, caused by diffusive-thermal effects. While the studied extreme points may appear sufficiently far from the leading edge of the instantaneous flame brush, leading points characterized by a lower, but still high ($Le<1$) FCR or HRR are observed close to the leading edge at each instant. Various local characteristics (temperature, equivalence ratio, species mass fractions and their gradients, reaction rates, etc.) of the extreme and leading points are explored and significant differences between zones characterized by high FCR or HRR are revealed. For instance, in the latter zones, major chemical pathways are changed. Moreover, while the extreme HRRs strongly fluctuate in time, with their mean and rms values being significantly increased by $Ka$, the extreme FCRs fluctuate weakly and are close at different $Ka$, thus, implying that almost the same extreme FCR can be reached in substantially different local burning structures.

以低路易斯数为特征的一维平面、贫化复杂化学氢-空气火焰的直接数值模拟 (DNS) 研究 $升\mathrm{电子}$ 和三个不同的卡洛维茨数$钾\mathrm{一种}$执行从 3 到 33 的范围，通过将所有物种的分子扩散率设置为等于混合物的热扩散率，还模拟了相同的复杂化学火焰。模拟预测前者的湍流燃烧速度与层流火焰速度的比率显着增加（$升\mathrm{电子}<1$) 火焰与后者（等扩散）火焰相比。以峰值（在计算域上）燃料消耗率 (FCR) 或热释放率 (HRR) 为特征的极值点在每个瞬间被发现。在等扩散火焰中，这种极端的 FCR 和 HRR 接近它们在未受干扰的层流火焰中的峰值。如果$升\mathrm{电子}$低，由于扩散热效应引起的局部温度、当量比和自由基质量分数的增加，前者的速率显着高于后者。虽然研究的极值点可能离瞬时火焰刷的前缘足够远，但领先点的特征是较低但仍然很高（$升\mathrm{电子}<1$) FCR 或 HRR 在每个时刻都靠近前沿观察到。探索了极端和领先点的各种局部特征（温度、当量比、物种质量分数及其梯度、反应速率等），并揭示了以高 FCR 或 HRR 为特征的区域之间的显着差异。例如，在后面的区域中，主要的化学途径发生了变化。此外，虽然极端 HRR 随时间发生强烈波动，但它们的均值和均方根值显着增加$钾\mathrm{一种}$, 极端 FCR 波动微弱，并在不同 $钾\mathrm{一种}$，因此，这意味着在完全不同的局部燃烧结构中可以达到几乎相同的极端 FCR。