Fuel effects on a low-swirl injector for lean premixed gas turbines

Laboratory experiments have been conducted to investigate the fuel effects on the turbulent prernixed flames produced by a gas turbine low-swirl injector (LSI). The lean-blow off limits and flame emissions for seven diluted and undiluted hydrocarbon and hydrogen fuels show that the LSI is capable of supporting stable flames that emit < 5 ppm NOx (@ 15% O-2). Analysis of the velocity statistics shows that the nonreacting and reacting flowfields of the LSI exhibit similarity features. The turbulent flame speeds, S-T, for the hydrocarbon fuels are consistent with those of methane/air flames and correlate linearly with turbulence intensity. The similarity feature and linear S-T correlation provide further support of an analytical model that explains why the LSI flame position does not change with flow velocity. The results also show that the LSI does not need to undergo significant alteration to operate with the hydrocarbon fuels but needs further studies for adaptation to burn diluted H-2 fuels. Published by Elsevier Inc. on behalf of The Combustion Institute.