Numerical predictions of oscillatory combustion in reactive multilayers

Current analytical models and recent experimental studies assume that exothermic formation reactions self-propagate in multilayer foils with steady temperature and composition profiles and uniform velocities. The numerical study presented here shows that in addition to steady propagation, oscillatory combustion can also exist in certain parameter regimes. The oscillatory regimes are characterized by superadiabatic temperature excursions and large variations in the reaction zone width, the flame thermal width, and the instantaneous flame velocity. The magnitudes of the oscillations are shown to increase as bilayer period decreases, as premixing in the as-deposited state increases, and as ambient temperature decreases.