Improving the combustion efficiency and agglomeration of aluminum-water propellants via n-Al/CuO metastable intermolecular composites

In this work, we investigated the combustion and agglomeration characteristics of aluminum-water propellants by replacing the original Al with binary n-Al/CuO metastable intermolecular composites (MICs). Through laser ignition tests and thermogravimetric-differential scanning calorimetry, we evaluated the oxidation reactivity, ignition delay, burning rate, agglomeration properties, and condensed combustion products of aluminum-water propellants containing different CuO loadings. Compared with conventional aluminum-water propellants, the introduction of binary MICs is found to lower the initial temperature of Al and improve its oxidation activity. Both the burning and heating rates scale linearly with the CuO loading, increasing by a factor of 5 and 6, respectively, when the CuO loading reaches 5 wt.%. The combustion efficiency of the modified propellants is found to improve by 5−12 %. The mean size of the condensed combustion products drops from over 400 μm to around 200 μm due to MICs addition, indicating weakened agglomeration. The ignition delay time is slightly shortened, and the combustion intensity first increases but then decreases as the CuO loading increases. In summary, this work indicates that replacing Al with binary Al/CuO-MICs can significantly alter the combustion and agglomeration properties of aluminum-water propellants. The experimental data and insight from this work could help guide the development of advanced aluminum-water propellants for various propulsion and energy applications.