Combustion of decane-based slurries with metallic fuel additives

Abstract

Low-density decane-based slurries were prepared with powders of mechanically alloyed Al0.7Li0.3, nanocomposite 2B + Ti, and pure aluminum. The slurries were atomized using an ultrasonic nozzle. The aerosol was focused into a laminar vertically rising jet and ignited in air to produce a lifted flame. Combustion was studied optically. It was found that aluminum was difficult to ignite. The powders of mechanically alloyed Al 0.7Li0.3 and nanocomposite 2B + Ti ignited readily and burned within the hydrocarbon flame, resulting in an increased flame temperature and length. Based on the visualized streaks, burning metal particles were well separated within the flame. The ignition of nanocomposite 2B + Ti particles was accompanied by a sharp increase in brightness and was often followed by particle microexplosions. The ignition delays of nanocomposite 2B + Ti particles were determined by the time of evaporation of liquid-fuel droplets in which metallic additives were contained. Ignition and combustion of the mechanically alloyed Al0.7Li0.3 was assisted by selective oxidation of Li. The flame length was controlled by the fuel and oxidizer diffusion rates. The flames containing mechanically alloyed Al0.7Li0.3 and nanocomposite 2B + Ti powders were longer than the pure decane flames and decane/Al slurry flames. The increased flame length indicated an additional consumption of oxidizer by metallic particles. Copyright © 2008 by the American Institute of Aeronautics and Astronautics, Inc.