Cellular structures of planar detonations with a detailed chemical reaction model

Two-dimensional computations of unsteady gaseous detonations have been performed using a detailed chemical reaction model. Five cases are simulated to reveal the structure and propagation of stoichiometric hydrogen-air or hydrogen-oxygen-argon detonations: 2H₂+ O₂+ 3.76N₂/3.76Ar at the initial pressures of 1.00, 0.421, and 0.132 atm. We examine the effects of channel width, initial pressure, and dilution and compare the results to the previous experimental data. Transverse wave strength determined by pressure ratio across the reflect shock is utilized for the evaluation of the transverse wave. With increasing the channel width, the transverse wave structure varies from the double Mach configuration to the complex double Mach configuration, and the transverse wave strength also increases. In hydrogen-air mixture at the initial pressure 1.00 and 0.421 atm, the strong transverse detonation, whose transverse wave strength is 1.5, propagates through the unreacted combustible mixture behind the incident shock. Our results indicate that an onset of the strong transverse detonation highly relates to the oscillation of the shock front and has a close relation to the second explosion limit of the gas mixture.