ID#: 136
Abstract Title: Multi-Headed Detonations in Oxygen-Aluminum Mixtures: Two-Dimensional Simulations Using Adaptive Grid Refinement
Session Title: Cellular Structure III
Session Date: 7/30/01
Session Start Time: 3:40 PM
Contributing Author: Benkiewicz, K.
Organization: Aoyama Gakuin University
Country: Japan
Authors: Krzysztof BENKIEWICZ, A. Koichi HAYASHI
Short Abstract: In the present paper the two-dimensional computer simulations of the detonation in the oxygen-aluminum particles mixture are presented. The continuous approach has been adopted. The gas phase is treated as the multi-component mixture that obeys thermally perfect equation of state. The solid phase burning is modeled using a simple formula that describes the solid/liquid aluminum consumption rate, while depending on the gas temperature the combustion products is either aluminum oxide (Al2O3) or aluminum monoxide (AlO). It is also assumed that at high temperatures (T>3500 [K]) aluminum oxide (Al2O3) starts to decompose into aluminum monoxide (AlO) and oxygen (O2). The computations have been performed using the Adaptive Mesh Refinement combined with the high-order, contemporary numerical methods. The AMR technique utilizes the set of hierarchical grid layers (patches) with increasing spatial resolution in order to improve the resolution near shocks, contact discontinuities or high gradients. This set of grid patches is self-adopting to the flow conditions. This technique leads to precise solution of the detonation front. The computations show the development of the triple points, incident shocks, Mach stems and local explosion centers. Finally the transition into the multi-headed detonation is observed. The structure of the detonation front and the flow field behind it are highly transient and complicated, and it is difficult to predict if this mode of propagation is stable or not. It is probably the first time when the detailed structure of the detonation front in the oxygen-aluminum mixture has been obtained in numerical simulations.