Influence of Sootshell Formation on Droplet Burning Rate and Radiative Heat Transfer in Microgravity Ethanol Droplet Combustion
- Paper number
IAC-09.A2.2.8
- Author
Dr. Seul Hyun Park, Drexel University, United States
- Coauthor
Mr. Mun Young Choi, University of Connecticut, United States
- Year
2009
- Abstract
The influence of sootshell formed in microgravity ethanol droplet flames on the droplet burning rate and radiative heat transfer was investigated through various measurements including the burning rate, soot standoff ratio, soot volume fraction, soot temperature and radiative heat losses. Microgravity ethanol droplet combustion experiments were performed at the NASA 2.2 s droptower in Cleveland, OH U.S.A. To quantitatively analyze the influence of sootshell on the burning rate and radiative heat transfer, the sootshell location was varied by means of inert gas substitution (argon vs. nitrogen). These experiments demonstrated strong influence of inert gas substitution (that caused changes in the thermophysical properties and temperature) between argon and nitrogen. The experimentally measured soot standoff ratio (SSR) for the argon inert experiment was ~1.4, whereas the value for the nitrogen inert experiment was ~ 2.5. The † Corresponding Author: Email:seulpark@nist.gov ; +1-975-301-3908 (O); +1-975-301-4052 (F)\ Current address: Building and Fire Research Laboratory (BFRL) National Institute of Standards and Technology (NIST) Gaithersburg, MD 20899-8662 calculated SSR for each of inert experiments using balance among Stefan, thermophoretic, and diffusiophoretic fluxes are also in excellent agreement with the experimental measurements. These experiments clearly indicate that the sootshell location influences the radiative heat transfer from the flame to the droplet and to the surrounding environment and can modify the burning rate. Keywords: Ethanol, Sootshell, Droplet Combustion, Microgravity, Radiative Heat Loss
- Abstract document
- Manuscript document
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