沉积环境下气膜冷却效率的实验

为了研究燃气涡轮叶片表面污染物沉积对气膜冷却的影响，通过将熔融石蜡喷入到小型风洞中，来模拟真实涡轮中的污染物，用平板近似代替涡轮叶片，在高温主流和低温冷流掺混的情况下，观察不同孔径和粗糙度对实验件表面颗粒物沉积的影响，以及在石蜡沉积后气膜冷却效果的变化趋势。结果表明，相同实验条件下，随着孔径的增大，气膜冷却效率逐渐增大，孔径为10 mm时的冷却效率比5 mm时的高6%左右，同时，平板表面的石蜡沉积逐渐减少，厚度相差0.15~0.20 mm；随着平板表面粗糙度的增加，气膜冷却效率逐渐下降，而石蜡沉积逐渐增多；较石蜡颗粒沉积前，沉积后的气膜冷却效率有较大的下降，效率相差5%左右。 

Experiment on gas film cooling efficiency in environment of deposition

In order to study the effect of deposition of pollutants on film cooling of gas turbine blades, the experiments were carried out by injecting molten paraffin wax into a small wind tunnel to simulate the pollutants in a real turbine. The blades were approximately replaced by flat plates. The experiments were carried out under mixing conditions of high temperature mainstream and low temperature cold flow. The influence of particulate matter deposition on the surface of the workpiece and the changing trend of film cooling effect after paraffin deposition. It was found that under the same experimental conditions, with the increase of the aperture, the film cooling efficiency increases gradually, and the cooling efficiency at the aperture of 10 mm is about 6% higher than that at 5 mm. At the same time, the paraffin deposition on the plate surface decreases gradually, and the thickness difference is 0.15-0.20 mm. With the increase of the surface roughness of the plate, the film cooling efficiency decreases gradually. However, the deposition of paraffin increases gradually, and the film cooling efficiency after deposition decreases greatly compared with that before the deposition of paraffin particles, with a difference of about 5%.