The influence of alternative fuel composition on gas turbine ignition performance

Increased interest in alternative aviation fuels and consequent advances in non-conventional refining techniques are providing for increased hydrocarbon diversification. Limited data however, exist on the complex relationships between these hydrocarbons and gas turbine combustion performance. The focus of this research was to determine the degree in which different fuel compositions affected ignition performance. Experimental ignition loops were obtained from representative combustion sections at atmospheric pressure. Selected fuels included: a gas-to-liquid synthetic (GTL), Jet A-1, a thermally stressed Jet A-1 and diesel. Results led to the conclusion that variation in fuel chemistry – including significant changes in hydrocarbon composition – does not influence ignition performance provided sufficient light hydrocarbons are available in the combustor primary zone. Further analysis of experimental results and fuel composition – through gas chromatography techniques (GC × GC) – facilitated the development of a mathematical correlation between the primary zone ignition equivalence ratio and the calculated test fuel vapour pressure.