Micro-explosion enhanced evaporation and combustion performance of high energy-density JP-10 emulsified fuel droplet stabilized by amphiphilic hyperbranched polyethyleneimine

Water-emulsified fuel represents a promising alternative fuel due to its potential to improve combustion efficiency through micro-explosions. In this work, a novel amphiphilic cetylated hyperbranched polyethyleneimine (CHPEI) was designed and synthesized as a surfactant for formulating a high energy-density JP-10 emulsified fuel, marking the first application of CHPEI in such a fuel system. The resulting emulsion demonstrates high stability at a low surfactant concentration, indicating exceptional emulsification efficiency. Single-droplet experiments revealed intense micro-explosions of emulsions during both evaporation and combustion. As a typical result, the emulsion droplets with 10% water exhibited a 43.9% reduction in evaporation lifetime compared to neat JP-10. The characteristics of micro-explosions were found to depend strongly on fuel composition: surfactant-only systems produced weaker (an intensity of 0.48 compared with 14.42) and less frequent (a frequency of 1 compared with 23) micro-explosions than the emulsion containing 10% water. Furthermore, increasing water content from 1% to 15% linearly enhanced the micro-explosion intensity. An optimal water content of 5% was identified, effectively balancing micro-explosion enhancement and the heat sink effect of water, which resulted in the shortest combustion lifetime. The emulsion with 5% water achieved a combustion energy release rate of 65.43 J·s −1 , which is 90.4% higher than that of neat JP-10 (34.36 J·s −1 ) and exceeded those of conventional fuels, including RP-3 (29.31 J·s −1 ), EHF-1 (32.69 J·s −1 ), and decalin (31.37 J·s −1 ). This work provides a practical design strategy to achieve high energy-density emulsified fuels with significantly enhanced combustion performance, offering valuable guidance for future fuel development.