Linking Fundamental Investigations and Engineering Results for Extinguishment of Fires on Solid Material

摘要-Vlachos CTS-9710413 这是对固体材料上发生的火灾的火焰熄灭的研究，因为通过直接冷却表面或通过热或化学试剂使氧化剂流惰性化，到表面的能量反馈减少。 本研究采用现代延拓方法对化学反应体系中的定态解进行数值计算。 数值结果解释一个新的灵敏度分析，简单的物理模型，火焰熄灭，和标准的渐近分析。 通过在恒定温度下用多孔气体燃烧器模拟热解材料，将气体燃烧动力学与表面能量平衡分离，其中燃料如甲烷或乙烯与氧化剂流一起燃烧。 研究的一个问题是，当灭绝的临界条件（例如无因次燃料供应）与达姆科勒数无关时。 对表面的火焰热反馈被计算为通过化学惰性或活性剂的燃料和/或氧化剂流的各种稀释和各种应变速率的质量供应速率的函数。 包括对流和辐射热反馈。 自史前时代以来，人们就一直使用经验性的灭火方法。 在过去的30年里，已经开发出了复杂的气体火焰熄灭模型，但这些模型很少能应用于固体表面上的火灾。 大多数有实际意义的固体材料的热解化学的细节是未知的。 目前，还没有一个通用的，鲁棒的策略来描述在不同的环境流动和环境条件下固体火灾的熄灭。 该项目概述了这样一种策略;它将最先进的流体相和化学模型以及非线性系统理论与可用的实验数据和消光测量技术相结合。

Abstract - Vlachos CTS - 9710413 This is an investigation of flame extinction of fires on solid materials occurring because the energy feedback to the surface decreases either by direct cooling of the surface or by inerting of the oxidant stream by a thermal or chemical agent. The study uses modern continuation methods for numerical calculation of stationary-state solutions in chemical reaction systems. Numerical results are interpreted with a novel sensitivity analysis, simple physical models for flame extinction, and standard asymptotic analysis. Gaseous combustion dynamics is separated from the surface energy balance by simulating the pyrolyzing material with a porous gaseous burner at a constant temperature in which a fule such as methane or ethylene burns with the oxidant flow. One isssue examined is when critical conditions for extinction, such as dimensionless fuel supply, are independent of the Damkohler number. The flame heat feedback to the surface is calculated as a function of mass supply rate for various dilutions of the fuel and/or oxidant streams by chemically inert or active agents and for various strain rates. Both convective and radiative heat feedback are included. Empirical methods for extinguishing fires have been used since prehistoric times. In the last thirty years, sophisticated models for extinction in gaseous flames have been developed, but little of this can be applied to fires on solid surfaces. Details of pyrolysis chemistry for most solid materials of practical interest are unknown. At present, no general, robust strategy exists to characterize extinction of solid fires under varioius ambient flow and environmental conditions. Such a strategy is outlined in this project; it integrates state-of-the-art fluid-phase and chemistry models and nonlinear systems theory with available experimental data and measurement techniques for extinction.