Combustion and emission characteristics of a novel staged combustor for aero gas turbine engine

To simultaneously achieve high combustion efficiency, low pollutant emissions, and robust stability in aero gas turbine engines, a novel staged combustor concept combining the trapped-vortex and swirl combustion characteristics is proposed in this study. In addition, experimental studies were conducted under atmospheric pressure to obtain insights into the combustion efficiency, pollutant emissions, stability, and flame features of the combustor. The results indicate that improving the air temperature (T3) and equivalence ratio is helpful for achieving high combustion efficiency. Interestingly, the pressure drop has a significant influence on the combustion efficiency at T3=373 K, whereas it has little influence at T3=473 K. The NOx emissions of the combustor increased as the air temperature increased, whereas, it decreased as the pressure drop increased. The lean blowout equivalence ratio increased slightly as the pressure drop increased, and was below 0.074 at T3=473 K. Two separated flames were formed inside and downstream of the cavities under pilot-only fueling conditions. For the pilot-main fueling conditions, three separated flames were observed at relatively low-equivalence ratio regimes. With the increases of the equivalence ratio, the three separated flames merge into one flame.