Comparison of Coupled Heat Transfer Characteristics of Effusion Cooling Walls with Different Hole Types Under Swirl Impact

Influence of hole configuration including cylindrical, fan-shaped and laidback fan-shaped holes on effusion cooling performance under different pressure drops of cooling air was examined using infrared thermal imaging technology. Results show that due to the vortex impact effect, low local cooling efficiency areas appear on the wall surface, which are independent of the hole type. The change in hole type only affects the cooling effect of the wall surface. Increasing the pressure drop of the cooling air can improve the cooling effect, and the area of the low cooling effect zone also decreases accordingly. The difference between the cooling hole shape and the pressure drop of the cooling air causes the movement of the lowest cooling effectiveness position on the wall. As the velocity of cooling air increases, this point moves upstream. In terms of the uniformity, the minimum effectiveness of cylindrical holes is lower by 14.3% to 27.5% than the area-averaged one. The difference between the minimum cooling efficiency of the fan-shaped hole, the expansion hole and the average level is greater, and the uniformity of the cooling effect is worse. The comprehensive cooling efficiency of the expansion hole is the highest, but the uniformity is the worst.