ISS: Flame Spread in Confined Spaces - Study of the Interactions between Flame and Surrounding Walls

本项目致力于研究受限空间内的火灾行为和火焰传播。根据2015年美国的数据，在所有火灾类型中，建筑火灾约占平民死亡人数的82%，财产损失的72%。通过提供对蔓延的火焰及其隔离墙之间的相互作用的基本了解，该项目将有助于实现更安全的设计和改进的消防安全规范。这些最终将减少财产损失、伤害和死亡。主要活动是将在国际空间站(ISS)上进行的燃烧实验。国际空间站上的微重力条件使人们能够系统地研究火灾对受限空间中不同空气流动环境的反应。研究人员还将使用他们最先进的计算工具来非常详细地模拟燃烧过程。除了为研究生提供教育机会外，该项目还将为大学生和高中生提供难得的机会，让他们在NASA Glenn研究中心获得亲身体验太空实验操作的机会。本研究的假设是，在一定条件下，火焰在密闭空间中的传播是一个持续加速的过程，可能会造成比在开放空间中的火焰传播更严重的火灾危险。允许这种情况发生的机制是来自周围墙壁的辐射热反馈和隧道流动加速效应。我们的目标是通过描述火焰壁的空气动力学和热相互作用来检验这一假设。平行流动火焰在平板样品上的传播试验将在微重力环境中的小流动管道中进行，在该微重力环境中，基本上消除浮力，强制流动施加在样品上，而不受其他参数的影响。将测试一系列参数，包括管道高度、样品材料、管道壁面特性和流速。这将伴随着一个内部暂态计算模型。计算结果将有助于解释实验数据，并允许外推到具有真实火灾规模的其他情况和几何形状。该项目的成果将提供缺失的知识，并导致对密闭空间中的火焰传播过程有更全面的了解。实验数据将为改进计算火灾模型提供有价值的信息。由此产生的模型将允许根据新的发现重新解释当前和过去的研究结果，这将导致火灾科学的新发现。

This project is focused on the study of fire behavior and flame spread in confined spaces. Structure fires account for approximately 82% of civilian deaths and 72% of property damage among all fire types, according to the 2015 U.S. data. By providing a fundamental understanding of the interactions between spreading flames and their confining walls, this project will help enable safer designs and improved fire safety codes. These will ultimately reduce property losses, injuries, and fatalities. The primary activity is the combustion experiment that will be conducted aboard the International Space Station (ISS). The microgravity conditions on the ISS enable a systematic examination of how fires respond to different air flow environments in confined spaces. The investigators will also use their state-of-the-art computational tools to model the combustion process in great detail. In addition to the educational opportunity to graduate students, this project will also provide rare opportunities for college and high school students to be "on console" at the NASA Glenn Research Center to have the first-hand experience of space experiment operations. The hypothesis of this research is that under certain conditions, flame spread in confined spaces is a continuously accelerating process and may pose an even more serious fire hazard than flame spread in open spaces. The mechanisms that allow this to occur are radiative heat feedback from the surrounding walls and the tunnel flow acceleration effect. The goal is to examine this hypothesis by characterizing flame-wall aerodynamics and thermal interactions. Tests of concurrent-flow flame spread over flat samples will be conducted in a small flow duct in the microgravity environment, where buoyancy is essentially eliminated, and the forced flow is imposed on the sample independent of other parameters. A wide range of parameters will be tested, including the duct height, sample material, duct wall surface properties, and flow speed. This will be accompanied by an in-house transient computational model. The computational results will help interpret the experimental data and allow extrapolations to other situations and geometries with realistic fire scales. The outcome of this project will provide missing knowledge and lead to a more complete understanding of the flame spread process in confined spaces. The experimental data will yield valuable information to enhance the computational fire model. The resulting model will allow re-interpretation of current and past research results in light of the new findings, which will lead to new discoveries in fire science.