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

本项目主要研究密闭空间内的火灾行为和火焰蔓延。根据2015年美国的数据，在所有类型的火灾中，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与其围墙之间相互作用的基本理解，该项目将有助于实现更安全的设计和改进消防安全规范。这将最终减少财产损失、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。在国际空间站的微重力条件下，可以系统地检查火灾对密闭空间中不同气流环境的反应。研究人员还将使用他们最先进的计算工具对燃烧过程进行非常详细的模拟。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，让他们能够在NASA格伦研究中心的“控制台”上获得第一手的空间实验操作经验。本研究的假设是，在一定条件下，密闭空间内的火焰传播是一个不断加速的过程，并且可能比开放空间的火焰传播造成更严重的火灾危险。使其发生的机制是来自周围壁的辐射热反馈和隧道流加速效应。目标是通过表征火焰壁空气动力学和热相互作用来检验这一假设。在微重力环境下，在一个小的流动管道中进行平面样品上的并行火焰蔓延试验，在该环境中浮力基本消除，强迫流动独立于其他参数施加在样品上。将测试广泛的参数，包括管道高度，样品材料，管道壁表面特性和流速。这将伴随着内部瞬态计算模型。计算结果将有助于解释实验数据，并允许外推到其他情况和具有现实火灾规模的几何形状。该项目的结果将提供缺失的知识，并导致对密闭空间中火焰传播过程的更完整的理解。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.