Dynamics of Ignition and Extinction Fronts on Diffusion Flame Sheets

本文采用分析方法和数值模拟相结合的方法，研究了扩散火焰片上点火和熄灭锋面（边缘火焰）的传播。本文验证了先前提出的抛物线火焰路径假设（PFPA）的适用范围和实用性，并将其纳入活化能渐近框架。系统检查包括消光锋面，碰撞三重火焰，和圆形点火锋面。这项工作对描述一些重要的实际现象具有指导意义，这些现象包括喷射火焰的起飞和熄灭、柴油机的自燃、火焰在燃料床上的蔓延以及湍流非预混燃烧中的局部熄灭。

This is a study of the propagation of ignition and extinction fronts (edge flames) on diffusion-flame sheets using a combination of analytical methods and numerical simulations. The scope and utility of the previously articulated parabolic flame path assumption (PFPA) and its incorporation into the activation-energy asymptotics framework are tested. Systems examined include extinction fronts, colliding triple flames, and circular ignition fronts. The work has implications for describing a member of important practical phenomena including lift-off and blow-out of jet flames, autoignition in diesel engines, flame spread over fuel beds, and local extinction in turbulent nonpremixed combustion.