Performance and Emissions Assessment of a Micro-Turbojet Engine Fueled with Jet A and Blends of Propanol, Butanol, Pentanol, Hexanol, Heptanol, and Octanol

Abstract

This study examines the impact of alcohol blends on the performance and emissions of aviation micro-turbojet engines. Thus, propanol, butanol, pentanol, hexanol, heptanol, and octanol were tested at 10%, 20%, and 30% concentrations and mixed with Jet A, as well as with an additional 5% heptanol blend to preserve base fuel properties, to fuel a JetCat P80 micro-turbojet. Physicochemical properties such as density, viscosity, and elemental composition were analyzed before engine testing. Carbon dioxide (CO2) emissions from 1 kg of fuel combustion varied, with propanol yielding the lowest at 3.02 kg CO2 per kg of fuel and octanol yielding the highest at 3.22 kg CO2 per kg of fuel. The following results were obtained: alcohol blends lowered exhaust gas temperature by up to 7.5% at idle and intermediate thrust but slightly increased it at maximum power; fuel mass flow increased with alcohol concentration, peaking at 20.4% above Jet A for 30% propanol; and thrust varied from −4.92% to +7.4%. While specific fuel consumption increased by up to 12.8% for propanol, thermal efficiency declined by 1.8–5.6% and combustion efficiency remained within ±2% of Jet A. Butanol and octanol emerged as viable alternatives, balancing emissions reduction and efficiency. The results emphasize the need for an optimal trade-off between environmental impact and engine performance.