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

Case Western Reserve University, Cleveland OH

Investigators

Abstract

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.