To solve the problems associated with micron-sized aluminum (Al), including sintering, agglomeration, and slag deposition during the combustion of aluminized propellants, aluminum–lithium (Al-Li) alloy, prepared by introducing a small amount of Li (1.0 wt.%) into Al, was used in place of Al. Then, the ignition and combustion characteristics of single micron-sized Al-Li alloy particles were investigated in detail using a self-built experimental apparatus and multiple characterization methods. The ignition probability, ignition delay time, flame propagation rate, burn time, combustion temperature, flame radiation spectra, and microexplosion characteristics were obtained. The TG-DSC results demonstrated that, as compared to the counterpart Al, the Al-Li alloy had a lower ignition temperature. The emission lines of AlO revealed the gas-phase combustion of the Al-Li alloy, and thus the Al-Li alloy exhibited a mixed combustion mode, including surface combustion and gas-phase combustion. Moreover, during combustion, a microexplosion occurred, which increased the combustion rate and reduced the burn lifetime. The ambient pressure had a significant effect on the ignition and combustion characteristics of the Al-Li alloy, and the ignition delay time and burn time exponentially decreased as the ambient pressure enhanced. The combustion temperature of the Al-Li alloy at atmospheric pressure was slightly higher than those at elevated pressures. The Al-Li alloy burned in N₂, but no microexplosion was observed. Finally, the ignition and combustion mechanism of the Al-Li alloy in air was demonstrated by combining SEM, EDS, and XRD analyses of the material and residues. The results suggest that the addition of Li promoted the combustion performance of Al by changing the surface structure of the oxide film and the combustion mode.

n-Decane-based nanofluid fuels could be one of the most promising alternative fuels as aviation kerosene for aerospace application. However, the physical and heat-transfer properties of n-decane-based nanofuels have been rarely studied, and the influence of the concentration of nanoparticles on the evaporation characteristics of n-decane-based fuels has been sparsely investigated. This paper investigated physical and heat-transfer properties and evaporation characteristics of graphite/n-decane nanofluid fuels and emphasized the concentration effect of adding graphite nanoplatelets (GNPs) on these characteristics. It was found that there are a linear increase of density and thermal conductivity, a binomial increase of viscosity, and a binomial influence on surface tension as GNP concentration increases, while the boiling point almost remains constant, and the latent heat of vaporization largely decays. There exists a critical GNP concentration of 1.75 wt % for the evaporation performance. At 0∼1.75 wt %, the increase of GNP concentration benefits the evaporation. At 1.75∼4.0 wt %, the enhancement of GNP concentration deteriorates the evaporation performance. A detailed discussion of this evaporation behavior was made, which could be attributed to multiple factors, for example, the aggregation of nanoplatelets, the changes of physical and heat-transfer properties owing to the nanoparticle concentration effect, the surfactant concentration, and the ambient temperature. The concentration of surfactants has a binomial effect, and the ambient temperature has a linear effect on the evaporation rate. This study would promote in depth understanding of physical and heat-transfer properties and evaporation characteristics of nanofluid fuels and develop the application in turbine engines and ramjet engines.