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Evaluation of Low-Gravity Smoke Particulate for Spacecraft Fire DetectionTests were conducted on the International Space Station to evaluate the smoke particulate size from materials and conditions that are typical of those expected in spacecraft fires. Five different materials representative of those found in spacecraft (Teflon, Kapton, cotton, silicone rubber and Pyrell) were heated to temperatures below the ignition point with conditions controlled to provide repeatable sample surface temperatures and air flow. The air flow past the sample during the heating period ranged from quiescent to 8 cm/s. The effective transport time to the measurement instruments was varied from 11 to 800 seconds to simulate different smoke transport conditions in spacecraft. The resultant aerosol was evaluated by three instruments which measured different moments of the particle size distribution. These moment diagnostics were used to determine the particle number concentration (zeroth moment), the diameter concentration (first moment), and the mass concentration (third moment). These statistics were combined to determine the diameter of average mass and the count mean diameter and by assuming a log-normal distribution, the geometric mean diameter and the geometric standard deviations were also calculated. Smoke particle samples were collected on TEM grids using a thermal precipitator for post flight analysis. The TEM grids were analyzed to determine the particle morphology and shape parameters. The different materials produced particles with significantly different morphologies. Overall the majority of the average smoke particle sizes were found to be in the 200 to 400 nanometer range with the quiescent cases and the cases with increased transport time typically producing with substantially larger particles. The results varied between materials but the smoke particles produced in low gravity were typically twice the size of particles produced in normal gravity. These results can be used to establish design requirements for future spacecraft smoke detectors.
Document ID
20140006585
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Urban, David (NASA Glenn Research Center Cleveland, OH United States)
Ruff, Gary A. (NASA Glenn Research Center Cleveland, OH United States)
Greenberg, Paul (NASA Glenn Research Center Cleveland, OH, United States)
Meyer, Marit (NASA Glenn Research Center Cleveland, OH, United States)
Mulholland, George (Maryland Univ. College Park, MD, United States)
Yuan, Zeng-guang (National Center for Space Exploration Research on Fluids and Combustion Cleveland, OH, United States)
Bryg, Victoria (National Center for Space Exploration Research on Fluids and Combustion Cleveland, OH, United States)
Cleary, Thomas (National Inst. of Standards and Technology Boulder, CO, United States)
Yang, Jiann (National Inst. of Standards and Technology Boulder, CO, United States)
Date Acquired
June 3, 2014
Publication Date
May 19, 2013
Subject Category
Mechanical Engineering
Space Transportation And Safety
Report/Patent Number
GRC-E-DAA-TN9488
Meeting Information
Meeting: U. S. National Combustion Meeting
Location: Park City, Utah
Country: United States
Start Date: May 19, 2013
End Date: May 22, 2013
Sponsors: Combustion Inst.
Funding Number(s)
CONTRACT_GRANT: NNX08AX49G
WBS: WBS 904211.04.02.30.19
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Fire
Fire Safety
Smoke

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