TY - JOUR
T1 - Combustion behaviors resulting from bimodal aluminum size distributions in thermites
AU - Moore, Kevin
AU - Pantoya, Michelle L.
AU - Son, Steven F.
N1 - Funding Information:
The authors gratefully acknowledge the support of the Army Research Office (Contract Number W911NF-04-1-0217) and the Los Alamos National Laboratory through the Advanced Energetics Initiative and the Defense Threat Reduction Agency (DTRA). Michelle Pantoya would also like to acknowledge helpful discussions with Tim Foley.
PY - 2007
Y1 - 2007
N2 - Studies that replace a portion of the micron-size aluminum (Al) with nano-Al particles in an energetic formulation demonstrate significant performance enhancement. Little is known, however, about the critical level of nano-sized fuel particles needed to enhance the performance of the energetic composite. Ignition sensitivity and combustion velocity experiments were performed using a thermite composed of Al and molybdenum trioxide (MoO 3). Both loose powders and compressed pellets were examined. A bimodal Al particle size distribution was prepared using 4 or 20-μm-diam Al fuel particles that were replaced in 10% increments by 80-nm-diam Al particles until the fuel was 100% nano-Al. Results show that with only 20% nano-Al content, the mixtures showed reduced ignition delay times by up to 2 orders of magnitude. The combustion velocity was shown to dramatically increase as more nano-Al particles replace micron-Al particles within the mixture. This increasing trend was attributed to incomplete reactions of the micron-Al particles or significantly slower reactions such that the micron-Al particles promote cooling or quenching of the reaction.
AB - Studies that replace a portion of the micron-size aluminum (Al) with nano-Al particles in an energetic formulation demonstrate significant performance enhancement. Little is known, however, about the critical level of nano-sized fuel particles needed to enhance the performance of the energetic composite. Ignition sensitivity and combustion velocity experiments were performed using a thermite composed of Al and molybdenum trioxide (MoO 3). Both loose powders and compressed pellets were examined. A bimodal Al particle size distribution was prepared using 4 or 20-μm-diam Al fuel particles that were replaced in 10% increments by 80-nm-diam Al particles until the fuel was 100% nano-Al. Results show that with only 20% nano-Al content, the mixtures showed reduced ignition delay times by up to 2 orders of magnitude. The combustion velocity was shown to dramatically increase as more nano-Al particles replace micron-Al particles within the mixture. This increasing trend was attributed to incomplete reactions of the micron-Al particles or significantly slower reactions such that the micron-Al particles promote cooling or quenching of the reaction.
UR - http://www.scopus.com/inward/record.url?scp=33847035611&partnerID=8YFLogxK
U2 - 10.2514/1.20754
DO - 10.2514/1.20754
M3 - Article
AN - SCOPUS:33847035611
VL - 23
SP - 181
EP - 185
JO - Journal of Propulsion and Power
JF - Journal of Propulsion and Power
SN - 0748-4658
IS - 1
ER -