Simulation of Double-Front Detonation of Suspended Mixed Cyclotrimethylenetrinitramine and Aluminum Dust in Air

The two-phase detonation of suspended mixed cyclotrimethylenetrinitramine （i.e., RDX） and aluminum dust in air is simulated with a two-phase flow model. The parameters of the mixed RDX-AI dust detonation wave are obtained. The double-front detonation and steady state of detonation wave of the mixed dust are analyzed. For the dust mixed RDX with density of 0.565kg/m3 and radius of 10μm as well as aluminum with density of 0.145kg/m3 and radius of 4μm, the detonation wave will reach a steady state at 23m. The effects of the size of aluminum on the detonation are analyzed. For constant radius of RDX particles with radius of 10μm, as the radius of aluminum particles is larger than 2.0 μm, the double-front detonation can be observed due to the different ignition distances and reaction rates of RDX and aluminum particles. As the radius of aluminum particles is larger, the velocity, pressure and temperature of detonation wave will be slower. The pressure at the Chapman-Jouguet （CJ） point also becomes lower. Comparing the detonation with single RDX dust, the pressure and temperature in the flow field of detonation of mixed dust are higher.

Numerical study on three-dimensional CJ detonation waves interacting with isotropic turbulence

The three-dimensional structures of a cellular detonation wave interacting with different turbulent flows were investigated using a one-step irreversible Arrhenius kinetics model. High-resolution bandwidth-optimized WENO scheme of spatial discretization and total variation diminishing temporal integration are used to solve the three dimensional chemically reactive Navier-Stokes equations. The turbulent vertical and entropic forcing effects on the three dimensional detonation wave structures and dynam- ics are analyzed, as well as the detonation effects on tur- bulent vortex structures. It has been found that the turbulence field imposed has created small scale wrinkles embedded in the detonation front, apart from the large scale features of detonation without turbulence. The deto- nation propagating velocity over the leading shock front varies from 0.8 to 1.6 times of CJ velocity and its proba- bility density function （pdf） skews towards sub-CJ velocity and peaks at about 0.9. The recorded detonation velocity always preferentially decays with time, with very rapid accelerations through triple point interactions. Its pdf also skews to sub-CJ velocity, while its overall shape agrees well with W3. The reaction zone is greatly influenced by the vortex, much more irregular and elongated for the turbulent cases. Distributed burning pockets are more likely to be found there. The turbulent kinetic energy is amplified across the detonation, and periodically oscillates downstream the detonation. The off-diagonal components of Reynolds stress also show a rapid rise across the deto- nation and present to be non-zero downstream of detona- tion. Vortex structures are compound results of the convected vortex and the generated vortex by the collision of triple points. The convection term and baroclinic gen- eration term in the transport equation of enstrophy are compared in detail.