TY - JOUR
T1 - Spherical gas-fueled cool diffusion flames
AU - Kim, Minhyeng
AU - Waddell, Kendyl A.
AU - Sunderland, Peter B.
AU - Nayagam, Vedha
AU - Stocker, Dennis P.
AU - Dietrich, Daniel L.
AU - Ju, Yiguang
AU - Williams, Forman A.
AU - Irace, Phillip
AU - Axelbaum, Richard L.
N1 - Funding Information:
This work was supported by NSF grant CBET-1740490 and the in-kind assistance of NASA and CASIS. The authors are grateful to the ISS crew members and the ISS operations team, particularly A. Adams and M. Smajdek, for their assistance. Helpful discussions with C.K. Law are appreciated.
Publisher Copyright:
© 2022 Elsevier Ltd. All rights reserved.
PY - 2022
Y1 - 2022
N2 - An improved understanding of cool diffusion flames could lead to improved engines. These flames are investigated here using a spherical porous burner with gaseous fuels in the microgravity environment of the International Space Station. Normal and inverse flames burning ethane, propane, and n-butane were explored with various fuel and oxygen concentrations, pressures, and flow rates. The diagnostics included an intensified video camera, radiometers, and thermocouples. Spherical cool diffusion flames burning gases were observed for the first time. However, these cool flames were not readily produced and were only obtained for normal n-butane flames at 2 bar with an ambient oxygen mole fraction of 0.39. The hot flames that spawned the cool flames were 2.6 times as large. An analytical model is presented that combines previous models for steady droplet burning and the partial-burning regime for cool diffusion flames. The results identify the importance of burner temperature on the behavior of these cool flames. They also indicate that the observed cool flames reside in rich regions near a mixture fraction of 0.53.
AB - An improved understanding of cool diffusion flames could lead to improved engines. These flames are investigated here using a spherical porous burner with gaseous fuels in the microgravity environment of the International Space Station. Normal and inverse flames burning ethane, propane, and n-butane were explored with various fuel and oxygen concentrations, pressures, and flow rates. The diagnostics included an intensified video camera, radiometers, and thermocouples. Spherical cool diffusion flames burning gases were observed for the first time. However, these cool flames were not readily produced and were only obtained for normal n-butane flames at 2 bar with an ambient oxygen mole fraction of 0.39. The hot flames that spawned the cool flames were 2.6 times as large. An analytical model is presented that combines previous models for steady droplet burning and the partial-burning regime for cool diffusion flames. The results identify the importance of burner temperature on the behavior of these cool flames. They also indicate that the observed cool flames reside in rich regions near a mixture fraction of 0.53.
KW - Formaldehyde
KW - Intensified video camera
KW - Microgravity combustion
KW - Porous burner
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U2 - 10.1016/j.proci.2022.07.015
DO - 10.1016/j.proci.2022.07.015
M3 - Article
AN - SCOPUS:85136084713
SN - 1540-7489
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
ER -