Simulations for Detonation Initiation Behind Reflected Shock Waves

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Numerical simulations are carried out for detonation initiation behind reflected shock waves in a shock tube. The two-dimensional thin-layer Navier-Stokes equations with chemical effects are numerically solved by use of a combined method consisting of the Flux-Corrected Transport scheme, the Crank-Nicolson scheme, and a chemical calculation step. Effects of chemical reactions occurring in a shock-heated hydrogen, oxygen, and argon mixture are estimated by using a simplified reaction model: two progress parameters are introduced to take account of induction reactions as well as exothermic reactions. Simulations are carried out referring to several experiments: generation of multidimensional and unstable reaction shock waves; strong and mild ignitions; and reacting shock waves in hydrogen and oxygen diluted in argon mixture. Introduction A reflected shock technique has been often utilized to investigate initiation of detonation, a series of processes such that a reaction front, generated behind a reflected shock wave, develops to a reaction shock wave which overtakes the reflected shock wave. Remarks from some experimental investigations, relating to the present numerical investigations, can be found in the following. Gilbert and Strehlow explained the detonation initiation process as a one-dimensional phenomenon, comparing their one-dimensional analyses with experimentally-determined distance-time diagrams of the detonation initiation behind reflected shock waves in a hydrogen, oxygen, and Copyright ©1993 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. * Professor, Department of Mechanical Engineering 283