Comparison-Effects of Broadened Property Jet Fuels on Older and Modern J79 Combustors Available to Purchase

The results of parallel investigations to determine the impacts of jet fuel property variations on the performance, life, and pollutant emission characteristics of two different J79 engine combustor designs are compared. One of the designs embodies older technology features. The other design was developed more recently and embodies several advanced technology features to provide lower smoke levels and longer liner life capabilities. Both combustors were evaluated with the same set of thirteen fuels. The fuels were selected to provide fuel property ranges which span those of current jet fuels and of possible future broadened-specification jet fuels. The modern technology combustor was found to be considerably more tolerant of fuel property variations than the older technology design. The relative insensitivity of the modern technology design is primarily attributed to its lean-burning features, which result in low smoke and low flame radiation levels even with low hydrogen content fuels.