Cellular detonation propagation and degeneration in bi-disperse gas suspensions of micron- and nano-sized aluminum particles

Abstract

Cellular detonation flows in bi-disperse oxygen suspensions of micron-, submicron-, and nano-sized aluminum particles are studied numerically on the basis of the semiempirical model of detonation. The transition from diffusion-limited combustion of micron-sized particles to the kinetic combustion regime of nano-sized aluminum particles is taken into account. The influence of the particle size and the mass fraction composition on the cellular detonation structure is analyzed. In micron- and submicron-sized bi-disperse mixtures, a degeneration of the cellular structure, with weakening and disappearance of the transverse waves, is observed for intermediate values of the mass fraction ratio. In bi-disperse mixtures of micron- and nano-sized particles, a gradual change in the detonation cell size and maximal pressure values with a variation of the mass fraction ratio is obtained. The numerical results are confirmed by acoustic analysis on the basis of Barthel’s method, which predicts the existence or absence of a regular system of transverse waves.