Study on Lean-Premixed Combustion Characteristics of Dual-Stage Burner

Key Words: Lean Premixed Combustor(희박예혼합연소기), Axial Swirl(축방향스월), NOx Emission(NOx배출), CO Emission(CO 배출), Staged Fuel Injection(단계별연료분사)초록: 본연구에서는가스터빈연소기에적용하기위한예혼합스월버너의배기가스및화염안정성최적화를위하여버너의구조변경에따른연소특성을실험적으로분석하였다. 버너의연료분사구조에따른배기가스배출특성을파악하고자단일연료분사구조와이중연료분사구조를갖는예혼합버너의연소특성을비교분석하였으며이중연료분사구조적용시연료/공기혼합특성이향상되어CO와NOx의배출농도가감소하는경향을나타내었다. 또한, 노즐출구와라이너의지름비(confined ratio)에따른연소부하및배기가스특성을분석한결과confined ratio 감소시연소부하감소로인해NOx 배출농도가감소되었으며, 체류시간의증가로인해CO의산화반응이증가하여CO 배출농도가감소하였다. 노즐분출속도는30 m/s에서배기가스특성이우수하며, 속도증가(40 m/s) 시배가스특성이저하되고속도감소(20 m/s) 시화염안정성이저하되었다.Abstract: This study aims to experimentally investigate the combustion characteristics of a lean premixedswirl-stabilized burner with dual-stage fuel injection arrays. The results show that a variation in the fueldistribution to fuel stages 1 (upstream) and 2 (downstream) produces a noticeable change in the NOx and COemissions. Reducing the confined ratio, defined as the ratio of the nozzle exit diameter to the liner diameter,may reduce NOx and CO emissions owing to reduced combustion loading and longer residence time,respectively. A nozzle exit velocity of 30 m/s shows the optimum characteristics in terms of NOx and COemissions and flame stability: increasing or decreasing the nozzle exit velocity leads to a degradation inemissions or flame stability, respectively.