Since its discovery, the flameless combustion (FC) regime has been a promising alternative to reduce pollutant emissions of gas turbine engines. This combustion mode is characterized by well-distributed reaction zones, which potentially decreases temperature gradients, acoustic oscillations, and NOx emissions. Its attainment within gas turbine engines has proved to be challenging because previous design attempts faced limitations related to operational range and combustion efficiency. Along with an aircraft conceptual design, the AHEAD project proposed a novel hybrid engine. One of the key features of the proposed hybrid engine is the use of two combustion chambers, with the second combustor operating in the FC mode. This novel configuration would allow the facilitation of the attainment of the FC regime. The conceptual design was adapted to a laboratory scale combustor that was tested at elevated temperature and atmospheric pressure. In the current work, the emission behavior of this scaled combustor is analyzed using computational fluid dynamics (CFD) andchemical reactor network (CRN). The CFD was able to provide informationwith the flow field in the combustor, while the CRN was used to modeland predict emissions. The CRN approach allowed the analysis of theNOx formation pathways, indicating thatthe prompt NOx was the dominant pathwayin the combustor. The combustor design can be improved by modifyingthe mixing between fuel and oxidizer as well as the split betweencombustion and dilution air.
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