Experimental Investigation of Flame-Film Cooling Interactions With an Academic Test Rig and Optical Laser Diagnostics

Abstract

The development of lighter low-carbon technologies in the aviation sector raises a technological challenge regarding material durability and wall thermal management. This study aims to introduce a new optically accessible test rig to investigate the interaction between a premixed CH4/air turbulent flame and a parietal cooling air film for various blowing ratios. Laser Doppler anemometry (LDA) is implemented to measure the cooling air and the mainstream inflow conditions. The impact of the blowing ratio on the mean flame topology is conducted with OH* chemiluminescence. Results show that the flame-wall distance increases with the blowing ratio and eventually reach a plateau, while the flame length constantly decreases. OH planar laser-induced fluorescence (OH-PLIF) and phosphor thermometry (PT) are performed to assess the near-wall flame structure and the cooling effectiveness. The flame seems to be aerodynamically controlled while the cooled-air momentum has a beneficial impact on the wall temperature.