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Liquid Fuels: Pyrolytic Degradation and Fire Spread Behavior as Influenced by BuoyancyThis work is being conducted by the Combustion and Emission Control Lab in the Engineering Department at Clark Atlanta University under NASA Grant No. NCC3-707. The work aims at providing data to supplement the ongoing NASA research activities on fire spread across liquid pools by providing flow visualization and velocity measurements especially in the gas phase and gas-liquid interface. The fabrication, installation, and testing were completed during this reporting period. The system shakedown and detailed quantitative measurements with High Speed Video and Particle Image Velocimetry (PIV) systems using butanol as fuel were performed. New and interesting results, not previously reported in the literature, were obtained from the experiments using a modified NASA tray and butanol as fuel. Three distinct flame spread regimes, as previously reported, were observed. These were the pseudo-uniform regime below 20 C, the pulsating regime between 22 and 30 C and the uniform regime above about 31 C. In the pulsating regime the jump velocity appeared to be independent of the pool temperature. However, the retreat velocity between jumps appeared to depend on the initial pool temperature. The flame retreated before surging forwards with increasing brightness. Previous literature reported this phenomenon only under microgravity conditions. However, we observed such behavior in our normal gravity experiments. Mini-pulsations behind the flame front were also observed. Two or three of these pulsations were observed within a single flame front pulsating time period. The velocity vector maps of the gas and liquid phases ahead, during, and behind the flame front were characterized. At least one recirculation cell was observed right below the flame front.The size of the liquid phase vortex (recirculation cell) below the flame front appeared to decrease with increasing initial pool temperature. The experiments also showed how multiple vortices developed in the liquid phase. A large recirculation cell, which generally spins counterclockwise as the flame spread from right to left, was observed ahead of and near the flame front in the gas phase. Detailed quantitative measurements will be undertaken with the LDV and PIV systems using the modified NASA tray and propanol.
Document ID
20020018892
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Yeboah, Yaw D.
(Clark-Atlanta Univ. GA United States)
Malbrue, Courtney
(Clark-Atlanta Univ. GA United States)
Savage, Melane
(Clark-Atlanta Univ. GA United States)
Liao, Bo
(Clark-Atlanta Univ. GA United States)
Ross, Howard D.
Date Acquired
August 20, 2013
Publication Date
November 1, 2001
Publication Information
Publication: HBCUs/OMUs Research Conference Agenda and Abstracts
Subject Category
Propellants And Fuels
Report/Patent Number
P11
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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