TY - GEN
T1 - Comparison of unstart induced by mass addition and heat release
AU - Im, Seong Kyun
AU - Wermer, Lydia
AU - Baccarella, Damiano
AU - Liu, Qili
AU - McGann, Brendan
AU - Do, Hyungrok
N1 - Funding Information:
Authors from the University of Notre Dame were supported by the U.S. Air Force Office of Scientific Research (AFOSR, FA9550-12-1-0161), monitored by Chiping Li of AFOSR. The authors gratefully acknowledge this source of support.
Publisher Copyright:
© 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All Rights Reserved.
PY - 2016
Y1 - 2016
N2 - The unstart phenomena in a model scramjet with the freestream of both low and high enthalpy Mach 4.5 flow conditions at an arc-heated hypersonic wind tunnel are investigated. Then, the unstart phenomena induced by a nitrogen or ethylene jet at low and high enthalpy conditions are compared. The nitrogen or ethylene jet pressurize downstream by mass addition and heat release from combustion. High-speed schlieren at the jet and the lip of the scramjet model inlet and high resonance frequency surface pressure measurements are used to capture flow features during an unstart process. In both conditions, the similar transient behavior of unstart shockwave system spawned by the flow choking and quasi-steady state of the unstart shockwave system at localized favorable pressure gradient are observed. In combustion driven unstart process, severe oscillatory flow motions of the jet and the unstart shockwave at the lip of the model inlet are observed. On the other hand, the unstarted flow motions triggered by mass addition remains relatively steady after the completion of the unstart process. The discrepancies between the unstart processes induced by the nitrogen and the ethylene jet are explained by flow choking analysis.
AB - The unstart phenomena in a model scramjet with the freestream of both low and high enthalpy Mach 4.5 flow conditions at an arc-heated hypersonic wind tunnel are investigated. Then, the unstart phenomena induced by a nitrogen or ethylene jet at low and high enthalpy conditions are compared. The nitrogen or ethylene jet pressurize downstream by mass addition and heat release from combustion. High-speed schlieren at the jet and the lip of the scramjet model inlet and high resonance frequency surface pressure measurements are used to capture flow features during an unstart process. In both conditions, the similar transient behavior of unstart shockwave system spawned by the flow choking and quasi-steady state of the unstart shockwave system at localized favorable pressure gradient are observed. In combustion driven unstart process, severe oscillatory flow motions of the jet and the unstart shockwave at the lip of the model inlet are observed. On the other hand, the unstarted flow motions triggered by mass addition remains relatively steady after the completion of the unstart process. The discrepancies between the unstart processes induced by the nitrogen and the ethylene jet are explained by flow choking analysis.
UR - http://www.scopus.com/inward/record.url?scp=85007444096&partnerID=8YFLogxK
U2 - 10.2514/6.2016-1168
DO - 10.2514/6.2016-1168
M3 - Conference contribution
AN - SCOPUS:85007444096
SN - 9781624103933
T3 - 54th AIAA Aerospace Sciences Meeting
BT - 54th AIAA Aerospace Sciences Meeting
PB - American Institute of Aeronautics and Astronautics Inc, AIAA
T2 - 54th AIAA Aerospace Sciences Meeting, 2016
Y2 - 4 January 2016 through 8 January 2016
ER -