Study on coupling characteristics between multi-swirler array combustor and NGVs

Abstract

A novel lean-burn burner effectively reduces NOx emissions from gas turbines, but residual swirl flow affects the NGV's performance. The multi-point array LDI combustor, as one type of lean-burn burner, lacks published articles on turbine coupling. This study conducts a comprehensive investigation of the coupling between the LDI combustor and the turbine for the first time. By analyzing the flow field characteristics using the SAS turbulence model, an innovative integrated design concept is proposed to address the challenges of combustion chamber-turbine integration. The aerodynamic and thermal characteristics of four different multi-swirler layouts are investigated. The findings indicate that compared to the conventional swirler arrangement, the multi-swirler configuration exhibits lower total pressure inhomogeneity, swirl angle, and secondary vortex intensity at the NGV. Furthermore, the multi-swirler configuration maintains the same temperature at the combustion chamber exit. The center swirler SW3 has a dominant influence on the swirler's orientation, with the endwall's thermal properties primarily affected by the clocking position. The PSW layout shows lower swirl stability and hot streaks intensity than NSW arrangement. NGV surface and exit temperature are less sensitive to the clocking position in both layouts. The PSW layout has a higher average swirl angle at the turbine inlet. The NSW arrangement has a larger fraction of momentum distribution and robust swirler stability, but hot streaks are considerable with a clear sinking consequence. A significant high temperature distribution is observed on the lower endwall and a clear thermal gradient near the exit. Both layouts show a high sensitivity of the upper endwall to clocking position. Overall, these findings provide valuable insights into the complex interactions between multi-swirler layouts and their aerodynamic and thermal characteristics, and highlight the importance of considering these factors in the design process.