Mathematical Sciences: Instabilities in Premixed and Diffused Flames

9403890 Matalon本程序涉及预混和扩散(非预混)火焰的动态行为。建议建立简化的数学模型，以描述开放和受限环境中一般形状的火焰，并在此框架内通过渐近和摄动方法并辅之以数值计算来研究火焰行为的动力学方面。将解决的具体问题包括确定与扩散火焰有关的内在不稳定性，探索由非均匀流场和限制引起的影响而复杂的预混火焰的动力学和稳定性，以及检查火焰在液体燃料上的传播动力学。拟议研究的意义在于加强对燃烧过程中涉及的复杂现象的当前理解。这项工作不仅对燃烧科学具有基础性的意义，而且对实际应用也有直接的意义。这项建议包括一个基础研究计划，其目的是从根本上了解复杂的化学和物理过程如何在真实的燃烧系统中相互作用。正在考虑的问题包括在开放和封闭环境中燃烧预混可燃气体，这是各种工程系统所关心的；火焰在易燃液体上蔓延，这在意外泄漏的火灾危险中是非常重要的；以及燃烧与消防安全和防火最相关的纯(非预混)燃料。为了深入了解这些问题，特别是对燃烧持续和灭火负责的机制，建议建立简化的数学模型并对其进行深入分析。这种确定因果关系的方法很可能解释和指导实验观察。深入的理解往往会为实验和设计提出新的方向。

9403890 Matalon This program is concerned with the dynamic behavior of premixed and diffusion (non-premixed) flames. It is proposed to derive simplified mathematical models that permit the description of flames of general shapes in open and confined environments, and to study dynamical aspects of flame behavior within this framework by means of asymptotic and perturbation methods supplemented by numerical computations. Specific problems that will be addressed include identifying intrinsic instabilities associated with diffusion flames, exploring the dynamics and stability of premixed flames complicated by non uniform flow fields and by effects due to confinement, and examining the dynamics of flame spread over liquid fuels. The significance of the proposed research is enhancement of the current understanding of the complex phenomena involved in combustion processes. The proposed work is not only of fundamental importance to combustion science but has also direct relevance to practical applications. This proposal consists of a basic research program whose aim is gaining fundamental understanding on how the complex chemical and physical processes interact in real combustion systems. The problems under consideration include the burning of premixed combustible gases in open and confined environments which is of interest in various engineering systems, flame spread over flammable liquids which is of great importance in fire hazards with accidental spillage, and the burning of pure (nonpremixed) fuels which is most relevant to fire safety and fire prevention. To gain insight into these problems, and in particular into the mechanisms responsible for the sustenance of the burning and those responsible for its extinguishement, it is proposed to develop simplified mathematical models and analyze them in depth. This approach, which identifies cause and effect, is likely to explain and guide experimental observations. A deep understanding often lead to suggest ions of new directions for experiments and design.