Flames, Flows and Their Interactions

层流火焰可以，在某些条件下，是固有的不稳定，导致褶皱或波纹结构。很明显，不稳定性的一般特征与潜在的流体流动和火焰锋面的热传递程度密切相关。分层混合物存在于许多燃烧环境中，形成弯曲且可能不稳定的火焰前缘。提出的研究旨在对层流预混火焰对流场中这种不均匀性的行为和响应有一个基本的理解。液滴蒸发和燃烧也将被研究。所使用的技术是用数值计算补充的渐近和摄动方法，并将结果与观测到的物理现象进行比较。人们对像发动机和炉膛这样复杂的系统的燃烧行为的理解，往往通过一个分离了一两个控制物理参数的简化描述的分析模型而得到加强。本理论研究将尝试扩展渐近和摄动技术在非均匀混合物中传播的预混火焰中的应用，目的是深入了解应变率、火焰锋面曲率、涡度、质量扩散、并且传热对火焰的稳定性有影响。

Laminar flames can, under certain conditions, be inherently unstable, leading to wrinkled or corrugated structures. It is clear that the general character of the instability is intimately tied to the underlying fluid flow and by the extent of heat transfer away from the flame front. Stratified mixtures exist in many combustion environments, creating a curved and possibly unsteady propagating flame front. The proposed research is directed towards a fundamental understanding of the behavior and response of a laminar, premixed flame to such non-uniformities in the flow field. Droplet vaporization and combustion will also be investigated. The techniques to be used are the asymptotic and perturbation methods supplemented by numerical calculations, with the results compared to observed physical phenomena. One's understanding of the behavior of combustion in systems as complex as engines and furnaces is often enhanced by an analytical model of a much simplified description which isolates one or two controlling physical parameters. This theoretical study will attempt to stretch the application of asymptotic and perturbation techniques to premixed flames propagating in non-uniform mixtures, with the objective of gaining insight into the effects of strain rate, flame front curvature, vorticity, mass diffusion, and heat transfer on the flame stability.