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Abstract Due to the need for enhanced gas turbine efficiency, the outlet temperature of the combustion chamber is increasing. Micromixed combustion (MMC) technology has been widely adopted in gas turbine combustion chambers to achieve low NOx emissions. In order to improve the performance of load regulation and inhibit thermoacoustic oscillations, this study investigates the effect of head-end fuel staging on the combustion characteristics of a multi-nozzle array model combustor through numerical simulations and experiments. The results demonstrate that employing different nozzle spacings effectively enables stable combustion. When only the pilot nozzle is operational, ignition stability is ensured by local flue gas recirculation zones from unit nozzles, as well as a large recirculation zone at the center of the combustion chamber. However, when both pilot and main nozzles are operational, expansion effects caused by high-temperature flue gas compress the central large recirculation zone. There is no significant impact on local flue gas recirculation zones between the pilot unit nozzles. The fluid dynamics within the model combustor guarantee its combustion stability and uniformity in outlet temperature under rated load conditions. NOx emissions are controlled through localized flue gas recirculation and flame lift-off mechanisms, which reduce the maximum temperature within the combustion chamber. The NOx emissions from this model combustor were found to be less than 25 ppm @15%O2.
Liu et al. (Mon,) studied this question.