TY - JOUR
T1 - Unstart phenomena induced by flow choking in scramjet inlet-isolators
AU - Im, Seong kyun
AU - Do, Hyungrok
N1 - Funding Information:
This work was supported by Basic Research Funding of Korean Agency for Defense Development (Project Number: 15-201-502-025 ) and National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) ( NRF-2017R1A4A1015523 ).
Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2018/2
Y1 - 2018/2
N2 - A review of recent research outcomes in downstream flow choking-driven unstart is presented. Unstart is a flow phenomenon at the inlet that severely reduces the air mass flow rate through the engine, causing a loss of thrust and considerable transient mechanical loading. Therefore, unstart in a scramjet engine crucially affects the design and the operation range of hypersonic vehicles. Downstream flow choking is known to be one of the major mechanisms inducing inlet unstart, as confirmed by recent scramjet-powered flight tests. The current paper examines recent research progress in identifying flow choking mechanisms that trigger unstart. Three different flow choking mechanisms are discussed: flow blockage, mass addition, and heat release from combustion reactions. Current research outcomes on the characteristic of unstarting flows, such as transient and quasi-steady motions, are reviewed for each flow choking mechanism. The characteristics of unstarted flows are described including Buzzing phenomena and oscillatory motions of unstarted shockwaves. Then, the state-of-the-art methods to predict, detect, and control unstart are presented. The review suggests that further investigations with high-enthalpy ground facilities will aid understanding of heat release-driven unstart.
AB - A review of recent research outcomes in downstream flow choking-driven unstart is presented. Unstart is a flow phenomenon at the inlet that severely reduces the air mass flow rate through the engine, causing a loss of thrust and considerable transient mechanical loading. Therefore, unstart in a scramjet engine crucially affects the design and the operation range of hypersonic vehicles. Downstream flow choking is known to be one of the major mechanisms inducing inlet unstart, as confirmed by recent scramjet-powered flight tests. The current paper examines recent research progress in identifying flow choking mechanisms that trigger unstart. Three different flow choking mechanisms are discussed: flow blockage, mass addition, and heat release from combustion reactions. Current research outcomes on the characteristic of unstarting flows, such as transient and quasi-steady motions, are reviewed for each flow choking mechanism. The characteristics of unstarted flows are described including Buzzing phenomena and oscillatory motions of unstarted shockwaves. Then, the state-of-the-art methods to predict, detect, and control unstart are presented. The review suggests that further investigations with high-enthalpy ground facilities will aid understanding of heat release-driven unstart.
KW - Flow choking
KW - Flow control
KW - Hypersonic propulsion
KW - Scramjet inlet-isolator
KW - Shockwave-boundary layer interaction
KW - Unstart
UR - http://www.scopus.com/inward/record.url?scp=85039921279&partnerID=8YFLogxK
U2 - 10.1016/j.paerosci.2017.12.001
DO - 10.1016/j.paerosci.2017.12.001
M3 - Review article
AN - SCOPUS:85039921279
VL - 97
SP - 1
EP - 21
JO - Progress in Aerospace Sciences
JF - Progress in Aerospace Sciences
SN - 0376-0421
ER -