IGNITION AND COMBUSTION OF ALUMINUM PARTICLES IN H-2 O-2/N-2 COMBUSTION PRODUCTS/

The ignition and combustion of aluminum particles is studied at high p ressures and temperature in the combustion products of nitrogen-dilute d premixed H-2/O-2 mixtures in a high-pressure, constant-volume combus tion chamber. A novel approach is used to inject particles after suffi cient delay for gas-phase combustion transients to equilibrate, permit ting the particles to ignite and burn at high ambient temperature and nearly constant pressure conditions. Particle ignition and combustion are monitored optically by measuring combusting particle emissions. Th e methodology is used to measure the ignition and combustion times of similar to 22-mu m spherodized aluminum particles over a range of pres sures (38-145 atm), at 2630 K, and in 20% excess oxygen concentration. Measured ignition delays and combustion times are compared to indepen dent data showing very good agreement.