An experimental study of detonation initiation in supersonic flow using a hot jet

In this study, detonation initiation in supersonic premixed flow is experimentally investigated using hot jets with different strength. Two types of shock interaction models, B/S (bow/separated) and S/S (sep-arated/separated), are observed, respectively. In the case with the high-strength hot jet, the ignition of the combustible mixture is triggered by the interaction between jet-induced bow and bottom separated shocks, which results in the generation of a Mach stem further initiating the detonation. Finally, the struc-ture of SSIC (separated shock-induced combustion)/LD (local detonation)/SSIC (separated shock-induced combustion) is observed. For the low-strength hot jet, detonation initiation could not be realized by the interaction between bow and separated shocks, and only the separated shock-induced combustion is ob-served. The interaction of shock surfaces in the flow field is dominated by the upper separated shock. Finally, a V-shaped SSIC/SSIC structure is generated associated with the forward propagation of separated shocks in the supersonic flow.(c) 2022 Published by Elsevier Inc. on behalf of The Combustion Institute.