The Influence of the Slot on The Effusion Cooling Performance with the Simulated Swirling Flow

An experimental study was conducted to investigate the influence of the slot jet on the cooling performance of a slot-effusion combined cooling scheme with a simulated swirling flow of the lean-burn combustor. PIV (particle image velocimetry) results show the slot jet reshapes the large-scale vortex structure and changes the lift-up effect of effusion jets. PSP (pressure-sensitive paint) results show there is still a region lacking the coverage of the slot coolant with an active slot, and here adiabatic cooling effectiveness ηad decreases downstream of holes. This phenomenon is enhanced by the lower effusion pressure drop. Consequently, the laterally averaged ηad shows an increase of 27% in the downstream of effusion plate when ΔP= 3%. While for ΔP=1% and 2%, the introduction of slot jet leads to an unchanged or slightly declined laterally averaged ηad in the region of 40<x / D<60. Moreover, the slot jet inhibits the lift-up effect of effusion jets when ΔP=3% resulting in a maximum rise of 180.0% for the area-averaged ηad. PIV and PSP results indicate the importance of the match for the pressure drops of the slot jet ΔW and effusion jetsΔP. From the present study, the same pressure drop (3%) for slot and effusion jet shows better cooling performance.