Effects of Ethanol, Butanol, and Isopropyl Alcohol Additives to Jet A-1 on Particulate Matter Emissions from a Mini-Scale Jet Engine

Alcohols have been investigated as blending components for Jet A-1 due to their oxygen content and renewable production potential, which may contribute to cleaner combustion and lower pollutant emissions. This study evaluates the effect of alcohol additives on particulate matter (PM) emissions from a mini-scale jet engine fueled with Jet A-1 blends. Ethanol, butanol, and isopropanol were investigated to determine their influence on PM formation. The results indicate that, on a fuel-mass basis, most of the tested alcohol blends generated lower PM emissions than neat Jet A-1 across the engine operating range, consistent with the expected oxidative benefit of oxygenated fuel additives. Ethanol 10% was a notable exception, showing PM emissions comparable to or exceeding those of neat Jet A-1 depending on engine thrust, in contrast to ethanol 5%, which consistently reduced PM emissions. This divergence between the two ethanol blend ratios indicates that the particulate response to alcohol addition does not scale monotonically with blend concentration. While alcohol additives have been reported to reduce PM emissions in other fuel applications, such as diesel engines, the results of this study show that this benefit is not uniformly guaranteed for aviation fuel and can depend strongly on both additive concentration and the engine operating point.