The re-initiation of cellular detonations downstream of an inert layer |
| |
| Institution: | 1. McGill University, Montreal, QC, Canada;2. Concordia University, Montreal, QC, Canada;3. University of Southampton, Southampton, United Kingdom;4. Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands;5. Eindhoven Institute of Renewable Energy Systems, Eindhoven University of Technology, Eindhoven, the Netherlands;1. Science and Technology on Scramjet Laboratory, National University of Defense Technology, Changsha, 410073, China;2. Science and Technology on Scramjet Laboratory, China Aerodynamics Research and Development Center, Mianyang, Sichuan, 621000, China;3. Aerodynamics and Flight Mechanics Research Group, University of Southampton, Boldrewood Innovation Campus, Southampton, SO16 7QF, United Kingdom;1. College of Power and Energy Engineering, Harbin Engineering University, Harbin, 150001, China;2. Department of Mechanical Engineering, National University of Singapore, Singapore, 117576, Singapore;3. Energy Systems Division, Argonne National Laboratory, IL, 60439, United States;1. CAPT, SKLTCS, College of Engineering, Peking University, Beijing 100871, China;2. LCP, Institute of Applied Physics and Computational Mathematics, Beijing 100094, China;1. Mechanical Engineering Program, Physical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia |
| |
| Abstract: | The current work aims to examine how the nature of cellular instabilities controls the re-initiation capability and dynamics of a gaseous detonation transmitting across a layer of inert (or non-detonable) gases. This canonical problem is tackled via computational analysis based on the two-dimensional, reactive Euler equations. Two different chemical kinetic models were used, a simplified two-step induction-reaction model and a detailed model for hydrogen-air. For the two-step model, cases with relatively high and low activation energies, representing highly and weakly unstable cellular detonations, respectively, are considered. For the weakly unstable case, two distinct types of re-initiation mechanisms were observed. (1) For thin inert layers, at the exit of the layer the detonation wave front has not fully decayed and thus the transverse waves are still relatively strong. Detonation re-initiation in the reactive gas downstream of the inert layer occurs at the gas compressed by the collision of the transverse waves, and thus is referred to as a cellular-instability-controlled re-initiation. (2) If an inert layer is sufficiently thick, the detonation wave front has fully decayed to a planar shock when it exits the inert layer, and re-initiation still occurs downstream as a result of planar shock compression only, which is thus referred to as a planar-shock-induced re-initiation. Between these two regimes there is a transition region where the wave front is not yet fully planar, and thus perturbations by the transverse waves still play a role in the re-initiation. For the highly unstable case, re-initiation only occurs via the cellular-instability-controlled mechanisms below a critical thickness of the inert layer. Additional simulations considering detailed chemical kinetics demonstrate that the critical re-initiation behaviors of an unstable stoichiometric mixture of hydrogen-air at 1 atm and 295 K are consistent with the finding from the two-step kinetic model for a highly unstable reactive mixture. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
