Two-dimensional numerical simulations of multi-headed detonations in oxygen-aluminum mixtures using an adaptive mesh refinement

Two-dimensional numerical simulations of detonations in two-phase lean mixtures of aluminum particles and pure oxygen have been performed. The computational procedure adopts an adaptive mesh refinement methodology in order to increase spatial resolution in the most interesting parts of the flow field. A one-step heterogeneous reaction describes the evaporation and combustion of aluminum. Depending on the gas-phase temperature, the combustion product is aluminum oxide or aluminum monoxide. The results show that the heterogeneous detonations resemble gaseous single-phase ones although the scale of the phenomena is very different. The detonation of 2.5 mum aluminum dust evolves into the 2-headed mode of propagation with the characteristic detonation cell width lambda(cell) equal to approximate to 6 cm. For 1 mum aluminum dust the cellular structure is much finer. The detonation initially propagates in the 11-headed mode with the characteristic cell width lambda(cell) equal to approximate to 1.1 cm and evolves into the 8.5-headed mode with the characteristic cell size lambda(cell) equal to approximate to 1.4 cm.