Experimental Study of an Instability in Buoyant Plumes and Diffusion Flames

在浮力占主导地位的扩散火焰中，反应锋发生周期性脉动，形成大尺度结构。这些结构类似于环形漩涡，在许多大型火灾中都可以观察到，是浮力驱动的不稳定性的结果。它们在离火源很近的地方形成，对空气进入火焰的夹带率有很大的影响。详细了解这一现象对于确定火灾中热气的产生非常重要，并对火灾的蔓延速度有很大影响。一项涉及流动可视化和振动刺激火焰不稳定性增强的详细研究将被执行，以表征这些类型的火焰，并为该过程的数值建模者提供有用的信息。＊＊＊

In buoyancy dominated diffusion flames, the reaction front undergoes periodic pulsations causing the formation of large scale structures. These structures, resembling toroidal vortices, are observable in many large fires and are a result of a buoyancy driven instability. They form very close to the source of the flame and have a large effect on the entrainment rates of air into these flames. A detailed understanding of this phenomenon is important for the determination of the hot gas production in a fire and strongly influences the fire spread rate. A detailed study involving flow visualization and vibrationally stimulated enhancement of the flame instabilities is to be performed to characterize these types of flames and provide information useful to numerical modelers of the process. ***