Study on Film Cooling Performance Improvement of NGV Leading Edge Subject to Distortion Profiles of Low NOx Combustor

Abstract

Under the effect of inlet distortion profiles (including hot-streaks, total pressure profiles, and swirling flow angle patterns), the film cooling performance on the leading edge (LE) region of GE-E3 nozzle guide vanes (NGVs) has been numerically investigated in this paper. Firstly, the complicated inlet distortion profiles of a low NOx combustor chamber has been decoupled to single factors to explore the individual and the coupling effects on the film cooling performance of the NGV LE region (Case 1 to Case 4). Then the original and three modified film-hole configurations are compared and discussed under the quasi-real environment (Case 5 to Case 8). The results indicate that total pressure profile tends to draw more coolant toward the midspan and the residual swirl promotes turnover of the cooling film to the other side of NGVs near the enwalls of LE region. Under the combined effects of different distortion profiles, the cooling film is redistributed on the LE region with some area near the stagnation lines with poor coverage. The upwash or downwash of boundary layer fluid caused by the complicated vortex in passages draws the cooling film on NGV surfaces. And this effect will be strengthened or weakened by the injection angles of holes. Finally, the filmhole configuration in Case 8 with counter-inclined film-hole rows arranged along the stagnation lines shows the best film cooling performance, which has positive effects on the decrease of high temperature region induced by hot streak (HS), and results in more uniform temperature distribution.