Comparison on combustion characteristics and energy release of μAl/JP-10, nAl/JP-10 and Al-Li/JP-10 suspension fuels

To improve the combustion efficiency of suspension fuels containing Al particles for aerospace, this work investigated the nanosizing and Al-Li alloying effects of Al on the combustion characteristics and energy release of JP-10-based suspension fuels. Microscale Al (μAl1 of 1–3 μm and μAl2 of 10–13 μm), nanoscale Al (nAl), and Al-Li particles were suspended in JP-10 with oleic acid (OA, 2.5–12.5 wt.%) at 1.0 wt.% and 5.0 wt.% particle loading. Combustion characteristics and energy release were analyzed by obtaining high-speed images, flame radiation spectra and temperature, and microscopic images of combustion residues. Results showed nAl enhanced micro-explosion intensity and energy release due to its high surface area, increasing flame temperature by 45.46 % and emission spectra intensity. Al-Li/JP-10 formed a porous oxide shell, enabling gas diffusion and stable micro-explosion, achieving the highest internal temperature of 702.7 °C and the fastest heating rate, with Li participation confirmed by 668 nm spectral peak. μAl2/JP-10 exhibited violent but inefficient combustion due to thick oxide shell. Residue analysis revealed Al-Li produced porous, fully oxidized agglomerates, while μAl retained unreacted cores. Nanosizing improved reactivity, while alloying enhanced combustion efficiency by disrupting oxide layer. These findings guide optimization of highly energetic suspension fuels via adjusting particle size and alloying strategies.