TY - JOUR
T1 - Combustion characteristics of a cavity flameholder with a burned-gas injector at the cavity bottom wall in a scramjet model combustor
AU - Yamaguchi, Tatsuya
AU - Hizawa, Tomohiro
AU - Yugami, Yasuto
AU - Hasegawa, Mariko
AU - Kudo, Taku
AU - Hayakawa, Akihiro
AU - Kobayashi, Hideaki
N1 - Publisher Copyright:
© 2020 The Japan Society for Aeronautical and Space Sciences.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020
Y1 - 2020
N2 - The combustion characteristics of the cavity flameholder with a burned-gas injector at the cavity bottom wall in the scramjet model combustor was investigated experimentally. The flame structure in the cavity was investigated by direct imaging and OH-PLIF measurement. As the result, four combustion modes were identified: jet-plume mode, jet-wake mode, one-sided cavity mode, and two-sided cavity mode. In response to the experimental results, the effects of the air-stream boundary layer thickness were additionally investigated numerically. Numerical results showed that an increase in the airstream boundary layer thickness adversely affected supported flameholding under conditions of a supersonic air-stream with low total temperature. When the airstream boundary layer becomes thicker, interaction between airstream and burned-gas jet creates a wider boundary layer separation upstream of the cavity leading edge. If the width of the separation region is greater than the width of the jet-plume, additional air entrainment path from separation region decreases static temperature inside the cavity flameholder, which makes supported flameholding difficult. It was concluded that the scramjet combustor needs suppression of the interaction between the supersonic airstream and burned-gas jet or avoidance of the boundary layer separation to avoid supported flameholding failure in a supersonic airstream with a thick boundary layer.
AB - The combustion characteristics of the cavity flameholder with a burned-gas injector at the cavity bottom wall in the scramjet model combustor was investigated experimentally. The flame structure in the cavity was investigated by direct imaging and OH-PLIF measurement. As the result, four combustion modes were identified: jet-plume mode, jet-wake mode, one-sided cavity mode, and two-sided cavity mode. In response to the experimental results, the effects of the air-stream boundary layer thickness were additionally investigated numerically. Numerical results showed that an increase in the airstream boundary layer thickness adversely affected supported flameholding under conditions of a supersonic air-stream with low total temperature. When the airstream boundary layer becomes thicker, interaction between airstream and burned-gas jet creates a wider boundary layer separation upstream of the cavity leading edge. If the width of the separation region is greater than the width of the jet-plume, additional air entrainment path from separation region decreases static temperature inside the cavity flameholder, which makes supported flameholding difficult. It was concluded that the scramjet combustor needs suppression of the interaction between the supersonic airstream and burned-gas jet or avoidance of the boundary layer separation to avoid supported flameholding failure in a supersonic airstream with a thick boundary layer.
KW - Burned-gas injection
KW - Cavity flameholder
KW - Combustion
KW - Scramjet engines
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U2 - 10.2322/tjsass.63.160
DO - 10.2322/tjsass.63.160
M3 - Article
AN - SCOPUS:85088389939
VL - 63
SP - 160
EP - 171
JO - Transactions of the Japan Society for Aeronautical and Space Sciences
JF - Transactions of the Japan Society for Aeronautical and Space Sciences
SN - 0549-3811
IS - 4
ER -