Experimental study on evaporation characteristics of aviation kerosene and sustainable aviation fuel at high temperature and pressure

To clarify the similarities and differences in the evaporation characteristics of sustainable aviation fuels (SAFs) and conventional aviation kerosene under high-pressure conditions, this study employed the suspended drop method. We systematically investigated the evaporation behavior of single droplets for two conventional aviation kerosenes (Jet A-1 and Jet A-2) and two SAFs (HEFA-1 and HEFA-2) with similar chemical compositions but different volatilities. The study covered a temperature range of 353 K to 553 K and a pressure range of 0.1 MPa to 0.6 MPa. Results indicated that the evaporation rate of all fuels generally increased with rising temperature. However, the effect of pressure on the evaporation rate was complex and dependent on both temperature and fuel type. At high temperatures (553 K), all fuels showed a monotonic increase in evaporation rate with increasing pressure. At moderate temperatures (453 K), all four fuels exhibited a non-monotonic trend in evaporation rate, which first decreased and then increased with pressure. This reflected a universal competition between mass transfer inhibition and near-critical promoting effects. The primary novelty of this work emerges from the distinct and divergent behaviors discovered under low-temperature (353 K), high-pressure conditions. The conventional kerosene fuels showed a non-monotonic trend in evaporation rate, which first decreased and then increased with pressure. In contrast, the two HEFA have distinctly different responses, HEFA-1 (low volatility) showed a monotonic in-crease in evaporation rate with pressure, while HEFA-2 (high volatility) showed a non-monotonic trend of first increasing and then decreasing. This divergence reveals that under the low-temperature, high-pressure regime, the evaporation mechanism is highly sensitive to the fundamental compositional differences between SAFs (pure alkanes) and conventional kerosene (containing aromatics and cycloalkanes). Through systematic comparison, this study reveals the similarities and differences in high-pressure evaporation behavior between SAFs and conventional kerosene, as well as the underlying physicochemical causes, providing crucial insights for the development and application of SAFs.