基于压力敏感漆的气膜冷却孔形实验研究

Experimental study of shaped hole film cooling using pressure sensitive paint

为改善燃气轮机热端部件的设计,使用压力敏感漆(PSP)技术对平板气膜冷却进行了实验研究。该技术基于压力敏感涂料氧猝熄光致发光特性,可进行表面压力和气膜冷却效率的测量。分别在不同温度和压力下对PSP的特性进行标定,并编写了实验后处理程序。实验给出了圆孔、扇形孔和扇形后倾孔3种孔型在吹风比为0.5、1.0和1.5时的气膜冷却效率分布。结果表明:圆孔在高吹风比时,冷却气流易吹离表面,冷却效果较差;扇形孔冷却效率随着吹风比的增加而增加,并具有较均匀的横向冷却分布;与扇形孔相比,扇形后倾孔增强了下游的冷气在孔中心线上的分布,减弱了其横向扩展。PSP技术具有分辨率高、可重复性好的特点,能有效用于气膜冷却流动和传热特性的研究。

A pressure sensitive paint （PSP） was used in plane film cooling tests to improve the design of the blades in a gas turbine. The PSP method, which is based on oxygen-quenched photoluminescence, can be used to measure surface pressures and the film cooling effectiveness. The paint was calibrated at several temperatures and pressures. The film cooling effectiveness distributions for cylindrical, fan shaped, and laidback fan shaped holes were measured at blowing ratios of 0.5, 1.0, and 1.5. The results indicate that for cylindrical holes, the film cooling effectiveness is reduced at high blowing ratios as the injected fluid is blown off the wall. For fan shaped holes, the film cooling effectiveness increases with the blowing ratio, with a more uniform spanwise distribution. The laidback fan shaped holes increase the centerline cooling flow distribution with a reduced spanwise spread. The study demonstrates that the PSP method is a precise, repeatable experimental method for film cooling heat transfer measurements.