Daniel Vaz

Most investigations on the implementation of flameless oxidation in gas turbines have been focused on the emissions aspects while the demonstration of the combustion acoustiCS improvement has been hardly ever addressed experimentally. The present experimental study provides insight into the differences of combustion generated noise between the conventional flame and flameless oxidation regimes. Results include noise levels measured in both combustion regimes, for different air-to-fuel ratios, and show an increased noise output in flame mode as compared to flameless oxidation. The paper also explains the acoustic precautions taken to allow comparison between cases.

The implementation of flue gas recirculation strategies for the reduction of NOx emissions in practical liquid fuelled burners is investigated. A laboratory furnace is used and the analysis is based on detailed spatial-resolved measurements of temperature and gaseous species concentrations. It is observed that, while air staging provides major reductions in NOx emissions, with reductions up to about 30%, the effect of adding hot combustion products to the air flow is mainly due to the increase in temperature which facilitates fuel vaporization, rather than to the expected effect of oxygen dilution. However, the aerodynamics of the near burner, which is determined by the operating conditions of the burner, has a greater effect on the NO x emissions than the vitiation of the combustion air.