Very lean hydrogen flames were thought to quench in narrow confined geometries. We show for the first time how flames with very low fuel concentration undergo an unprecedented propagation in narrow gaps: H${}_2$-air flames can survive very adverse conditions by breaking the reaction front into isolated flame cells that travel steadily in straight lines or split to perform a fractal-like propagation that resembles the pathway of starving fungi or bacteria. The combined effect of hydrogen mass diffusivity and intense heat losses act as the two main mechanisms that explain the experimental observations.

中文翻译：

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超贫氢火焰在狭窄间隙中的意外传播

人们认为非常稀薄的氢火焰会在狭窄的密闭几何形状中淬火。我们首次展示了燃料浓度非常低的火焰如何在狭窄的间隙中发生前所未有的传播：H${}_2$空气火焰可以通过将反应前沿分解为稳定的直线形或连续分裂成类似于饥饿的真菌或细菌途径的分形传播的孤立的火焰细胞，从而在非常不利的条件下生存。氢质量扩散率和强烈的热损失的共同作用是解释实验观察的两个主要机理。