The combustion performance of a wide range of fuel types has been examined utilizing a single combustor from a Rolls-Royce Tyne gas-turbine engine. The results provide further evidence to suggest that fuel total hydrogen content provides a better indication of fuel combustion perfomance than does aromatic content. However, an even better prediction of fuel combustion performance is given by smoke point, although the acknowledged imprecision of the smoke point test does militate against its use as a primary specification requirement.
Analysis of certain fuels by 13C NMR and low resolution mass spectroscopy demonstrates that it is those fuels with high concentrations of polycyclic aromatics whose combustion performance in terms of flame radiation and exhaust emissions, is underpredicted by fuel total hydrogen content. There are indications that low concentrations of high molecular weight polycyclic aromatics may substantially impair combustion performance.