TY - JOUR
T1 - Flame dynamics under various backpressures in a model scramjet with and without a cavity flameholder
AU - Kato, Nozomu
AU - Im, Seong Kyun
N1 - Funding Information:
This work was supported by Basic Research Funding from the Korean Agency for Defense Development (Project Number: 16-106-501-035 , sub-project number 3). Seong-kyun Im was supported by Korea University research grants.
Publisher Copyright:
© 2020 The Combustion Institute.
PY - 2021
Y1 - 2021
N2 - Flame dynamics under various backpressure conditions were experimentally investigated using direct flame visualization, high-speed CH∗chemiluminescence imaging, and wall pressure measurements. The stagnation pressure and temperature used in the present study were 100 kPa and 2500 K, respectively, with a freestream Mach number of 4.5. Rectangular scramjet models with and without a cavity were used to explore the effects of the cavity on flame dynamics when operating in scramjet mode, ramjet mode, and unstart. The flow rate of the ethylene jet was varied to impose backpressures corresponding to each operation mode. For both models, reverse flame propagation was observed for ramjet mode and unstart. For ramjet mode, flame fluctuation occurred within the isolator due to the coupling of fluid dynamics and combustion. The presence of a cavity enhanced combustion and reduced flame fluctuation in both scram and ramjet mode. The cavity promoted unstart because of the greater heat release from combustion. Further research using spatially resolved diagnostic techniques is needed to identify the flame locations for ramjet mode and unstart.
AB - Flame dynamics under various backpressure conditions were experimentally investigated using direct flame visualization, high-speed CH∗chemiluminescence imaging, and wall pressure measurements. The stagnation pressure and temperature used in the present study were 100 kPa and 2500 K, respectively, with a freestream Mach number of 4.5. Rectangular scramjet models with and without a cavity were used to explore the effects of the cavity on flame dynamics when operating in scramjet mode, ramjet mode, and unstart. The flow rate of the ethylene jet was varied to impose backpressures corresponding to each operation mode. For both models, reverse flame propagation was observed for ramjet mode and unstart. For ramjet mode, flame fluctuation occurred within the isolator due to the coupling of fluid dynamics and combustion. The presence of a cavity enhanced combustion and reduced flame fluctuation in both scram and ramjet mode. The cavity promoted unstart because of the greater heat release from combustion. Further research using spatially resolved diagnostic techniques is needed to identify the flame locations for ramjet mode and unstart.
KW - Cavity flameholder
KW - Scramjet engine
KW - Supersonic combustion
UR - http://www.scopus.com/inward/record.url?scp=85091494961&partnerID=8YFLogxK
U2 - 10.1016/j.proci.2020.07.110
DO - 10.1016/j.proci.2020.07.110
M3 - Conference article
AN - SCOPUS:85091494961
VL - 38
SP - 3861
EP - 3868
JO - Proceedings of the Combustion Institute
JF - Proceedings of the Combustion Institute
SN - 1540-7489
IS - 3
T2 - 38th International Symposium on Combustion, 2021
Y2 - 24 January 2021 through 29 January 2021
ER -