EFFUSION COOLING CHARACTERISTICS OF EFFUSION-COOLED COMBUSTOR LINERS WITH DIFFERENT HOLE CONFIGURATIONS UNDER SWIRL IMPACT

The conjugate cooling characteristics of effusion-cooled n-shaped holes, were compared with the combustor widely used cooling air pressure drop (ΔPcool) ranging from 0.08% to 1.90%. All plates were covered by a thermal barrier coating. The cooling effectiveness distribution correlates closely to the swirl impact. In specific, there appear two low-effectiveness regions due to the swirl impact. The area of the regions for the cylindrical holes account for 37.52% to 13.77% of the plate as the cooling air pressure drop increases, and the fan-shaped and laidback fan-shaped holes have gradually smaller area. The lowest effectiveness for the cylindrical holes is 27.5% to 14.3% lower than the average, and for the fan-shaped and laidback fan-shaped holes the value increases, meaning greater dis-uniformity of cooling effectiveness. In terms of the cooling performance, the laidback fan-shaped holes are the best, 0.05 higher than the worst cylindrical holes in cooling effectiveness. The points that are lowest in cooling effectiveness, migrate along the center line of the regions forward as the pressure drop increases and downstream as the hole outlet expands since the increasing of outlet velocity of cooling holes is significant for the resistance of swirl impact.