Combustion enhancement of sustainable aviation fuel containing ethanol in aero jet engine combustors by regulating the intrinsic characteristics of the fuel

Sustainable aviation fuels (SAFs) manufactured from green feedstocks are desired as fuels for traditional aviation jet engines to address the emissions problems. Bio-ethanol, as a renewable energy fuel, is very compatible with hydrocarbon fuels. However, the poor low-temperature start-up and operating performance of bio-ethanol due to the high latent heat of evaporation hinders the application advantages of renewable aviation fuel containing ethanol in jet engines. In this study, the regulation of the intrinsic properties of fuel was proposed to solve the above problem. The mechanism of the combustion enhancement by co-evaporation and in-situ generation of free radicals for the oxidation of alkanes in the hybrid fuel was analyzed by thermogravimetry-Fourier transform infrared experiments. Single-sector combustion chamber ignition experiments showed that modified fuels can extend the ignition boundaries, allowing fuel ignition at lower fuel-air equivalence ratios (0.015). In addition, flameout experiments showed that E30/K70-10 can broaden the flameout fuel-air equivalence ratio of fuel (from 0.018 to 0.014), attributed to improved oxidation, evaporation, and basic atomization performance. This study provides a reference for the use of ethanol-based SAF in advanced aircraft engines to improve ignition performance and extend the limits of real engine flameout.