Effects of ‘Oxy’ jet in cross flow on the combustion instability and NOx emissions in lean premixed flame

Abstract

Combustion instability and nitrogen oxides emission are crucial factors for modern gas turbine combustors, which seriously hampers the research and development of advanced combustors. To eliminate combustion instability and NOx emissions simultaneously, effects of the ?Oxy? (CO2/O2, N2/O2, Ar/O2and He/O2) jet in cross flow(JICF)on combustion instability and NOx emissions are experimentally studied. In this research, the flow rate and oxygen ratio of the combustor are varied to evaluate the control effectiveness. Results denotes that all the four oxy fuel gas: CO2/O2, N2/O2, Ar/O2and He/O2, could suppress combustion instability and NOx emissions. The CO2/O2dilution can achieve a better damping results than the other three cases. There are peak values or lowest points of sound pressure amplitude as the parameter of ?Oxy? JICF changes. Mode transition appears in both acoustic signal and CH* chemiluminescence of the flame. But the turning point of mode transition is different. Under the CO2/O2cases, the NOx emission decreases from 22.3ppm to 15.2ppm, the damping ratio of NOxis 40.39%. The flame shape and length were changed under different JICF dilutions. This research could promote the application of jet in cross flow methods on combustion instability or pollutant emissions in gas turbines.