年間 6 号発行
ISSN 印刷: 2150-766X
ISSN オンライン: 2150-7678
Indexed in
ANALYSIS OF BORON PARTICLE IGNITION ABOVE A BURNING SOLID FUEL IN A HIGH-VELOCITY ENVIRONMENT
要約
The ignition processes of boron particles above a burning solid fuel have been studied by numerical solution of a comprehensive theoretical model. The gas-phase formulation is based on the time-dependent multi-dimensional compressible Navier-Stokes equations and species transport equations. The particle-phase solution is obtained using a well-established boron particle ignition model. Boron particles are ejected from the surface of the burning fuel into a high-velocity crossflow and their trajectories are traced through the reacting flowfield using a Stochastic Separated Flow approach. The effects of particle size on their ignition time and location are determined. Results indicate that small particles (d < 3 μm) ignite as soon as they pass through the gas-phase reaction zone and come in contact with oxygen. Larger particles ignite further downstream, since they require more energy to remove their oxide layers and achieve thermal runaway. The effects of ambient conditions on the ignition times are also investigated. The study shows that minimization of ignition time can be accomplished by optimizing the environmental conditions during the ignition process.