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Author (up) Carmignani, L.; Garg, P.; Thomsen, M.; Gollner, M.J.; Fernandez-Pello, C.; Urban, D.L.; Ruff, G.A.
Title Effect of sub-atmospheric pressure on the characteristics of concurrent/upward flame spread over a thin solid Type
Year 2022 Publication Combustion and Flame Abbreviated Journal Combust. Flame
Volume 245 Issue Pages 112312
Keywords Upward flame spread; Heat release rate; Acrylic fuel; Pressure modeling
Abstract The variation of ambient pressure is a potential tool for studying the driving parameters of fire dynamics and heat release in low-pressure environments such as high-altitude locations, aircraft, and spacecraft. The study of upward flame spread over a solid fuel has direct implications on material flammability and fire development, and low pressure environments have recently gained more attention for the possible comparison with the reduced gravity conditions encountered during space missions. In this work, we consider upward spreading flames over thin acrylic sheets in ambient pressures between 30 and 100 kPa. A forced flow velocity of 20 cm/s is added to the naturally-driven buoyant flow, creating a mixed flow field (natural and forced) that varies with pressure. Flame characteristics such as spread rate and standoff distance are measured from the video analysis of the experiments. It is observed that the former decreases with pressure while the latter increases. The larger flame stand-off distance at low pressures partially explains the decrease of the flame spread rate since the convective heat flux from the flame to the solid decreases. Additionally, volumetric concentrations of the combustion products are measured during the experiments. The results show lower O-2 consumption and CO2 production rates at lower pressures. Based on these rates, we could calculate the heat release rate from upward spreading flames at low pressure, providing fundamental information for better understanding pressure-gravity correlations. According to the results, the volumetric heat release rate is proportional to pressure, which is consistent with previous studies on pressure modeling of fires. This suggests that chemical kinetics is not a constraint for the conditions tested in this study, which could help make future flammability tests comparable to low gravity ones.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0010-2180 ISBN Medium
Area Expedition Conference
Notes WOS:000861453100006 Approved
Call Number UAI @ alexi.delcanto @ Serial 1688
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Author (up) Manzello, S.L.; Blanchi, R.; Gollner, M.J.; Gorham, D.; McAllister, S.; Pastor, E.; Planas, E.; Reszka, P.; Suzuki, S.
Title Summary of workshop large outdoor fires and the built environment Type
Year 2018 Publication Fire Safety Journal Abbreviated Journal Fire Saf. J.
Volume 100 Issue Pages 76-92
Keywords
Abstract Large outdoor fires present a risk to the built environment. Wildfires that spread into communities, referred to as Wildland-Urban Interface (WUI) fires, have destroyed communities throughout the world, and are an emerging problem in fire safety science. Other examples are large urban fires including those that have occurred after earthquakes. Research into large outdoor fires, and how to potentially mitigate the loss of structures in such fires, lags other areas of fire safety science research. At the same time, common characteristics between fire spread in WUI fires and urban fires have not been fully exploited. In this paper, an overview of the large outdoor fire risk to the built environment from each region is presented. Critical research needs for this problem in the context of fire safety science are provided. The present paper seeks to develop the foundation for an international research needs roadmap to reduce the risk of large outdoor fires to the built environment.
Address [Manzello, Samuel L.] NIST, Fire Res Div, Gaithersburg, MD 20899 USA, Email: samuelm@nist.gov
Corporate Author Thesis
Publisher Elsevier Sci Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0379-7112 ISBN Medium
Area Expedition Conference
Notes WOS:000445981000008 Approved
Call Number UAI @ eduardo.moreno @ Serial 919
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Author (up) Thomsen, M.; Carmignani, L.; Rodriguez, A.; Scudiere, C.; Liveretou, C.; Fernandez-Pello, C.; Gollner, M.; Olson, S.; Ferkul, P.
Title Downward Flame Spread Rate Over PMMA Rods Under External Radiant Heating Type
Year 2022 Publication Fire Technology Abbreviated Journal Fire Technol.
Volume 58 Issue 4 Pages 2229-2250
Keywords Flame spread; Radiant heating; PMMA rod; Solid burning; SoFIE
Abstract There are multiple situations in which fires may occur at environmental conditions that are different than standard atmospheric conditions. Changes in ambient pressure, oxygen concentration, flow velocity, the presence of an external heat source or gravity may change the flammability and fire dynamics of materials. The objective of this work is to study the effect of external radiant heating on downward flame spread over cylindrical samples of polymethyl methacrylate (PMMA). In this work, experiments under normal gravity and atmospheric ambient conditions are conducted using a variable heat flux with peak values up to 13.2 kW/m(2). A forced flow of air with a mass-mean velocity of 10 cm/s is used during the experiments. Flame spread rates were measured from video processing of the experiments at different conditions. Results show that the flame spread rate measured depends strongly on the amount of radiant heating provided. An analysis is presented to correlate the flame spread rate with the energy applied to the surface of the sample and the surface temperature. The results provide a baseline for comparison with future microgravity experiments to be performed by NASA as part of the SoFIE/MIST project aboard the International Space Station. It is expected that the results will provide insight for what is to be expected in different conditions relevant for fire safety in future space facilities.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0015-2684 ISBN Medium
Area Expedition Conference
Notes WOS:000789722000001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1568
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Author (up) Thomsen, M.; Cruz, J.J.; Escudero, F.; Fuentes, A.; Fernandez-Pello, C.; Gollner, M.; Urban, D.L.; Ruff, G.A.
Title Determining flame temperature by broadband two color pyrometry in a flame spreading over a thin solid in microgravity Type
Year 2023 Publication Proceedings Of The Combustion Institute Abbreviated Journal Proc. Combust. Inst.
Volume 39 Issue 3 Pages 3909-3918
Keywords Broadband pyrometry; Soot temperature; Boundary layer diffusion flame; Concurrent flame spread; Sibal material
Abstract Fire spread inside a spacecraft is a constant concern in space travel. Understanding how the fire grows and spreads, and how it can potentially be extinguished is critical for planning future missions. The conditions in-side a spacecraft can greatly vary from those encountered on earth, including microgravity, low velocity flows, reduced ambient pressure and high oxygen, and thus affecting the combustion processes. In microgravity, the contributions of thermal radiation from gaseous species and soot can play a critical role in the spread of a flame and the problem has not been fully understood yet. The overall objective of this work is to address this by studying the soot temperature of microgravity flames spreading over a thin solid in microgravity. The ex-periments presented here were performed as part of the NASA project Saffire IV, conducted in orbit on board the Cygnus resupply vehicle before it re-entered the Earth's atmosphere. The fuel considered is a thin fabric made of cotton and fiberglass (Sibal) exposed to a forced flow of 20 cm/s in a concurrent flow configuration. Reconstruction of the flame temperature fields is extracted from two color broadband emission pyrometry (B2CP) as the flame propagates over the solid fuel. A methodology, relevant assumptions and its applicability to other microgravity experiments are discussed here. The data obtained shows that the technique provides an acceptable average temperature around similar to 1300 K, which remains relatively constant during the spread with an error value smaller than 117 K. The data presented in this work provides a methodology that could be applied to other microgravity experiments to be performed by NASA. It is expected that the results will provide insight for what is to be expected in different conditions relevant for fire safety in future space facilities. (c) 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1540-7489 ISBN Medium
Area Expedition Conference
Notes WOS:001058486000001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1879
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