纵向波纹隔热屏气膜冷却特性实验

针对加力燃烧室纵向波纹隔热屏气膜冷却效果开展了细致的实验研究,利用红外热像仪测量了隔热屏壁面的温度分布,分析了隔热屏板型、吹风比、开孔率等参数对气膜冷却效率的影响。实验中板型选取了平板和纵向波纹隔热屏,吹风比变化范围是0.5~3.0,开孔率变化范围是1.4%~3.7%。结果表明:相比于平板隔热屏的气膜冷却效率沿程逐渐增加,纵向波纹隔热屏的气膜冷却效率随波纹板的起伏而起伏且大于平板隔热屏;随着吹风比的增加气膜冷却效率逐渐加大,在吹风比为3.0时达到最大值;气膜冷却效率在波峰处低,波谷处高,整体上随波纹板的起伏而波动,吹风比越小,气膜冷却效率随波纹板的起伏变化越明显;高吹风比(吹风比为2.0~3.0)下,气膜冷却效率沿程变化与增幅较为缓慢;整体上,随着开孔率的增加气膜冷却效率逐渐加大,小开孔率(开孔率为1.4%、2.7%)下的气膜冷却效率相差不大,但在次流背风侧,开孔率小的气膜冷却效率要小于开孔率大的气膜冷却效率。 

Experiment on film cooling characteristics for longitudinal corrugated heat-shield

Detailed experimental study on film cooling effect of one afterburner longitudinal corrugated heat-shield was carried out. The surface temperature distribution of the heat-shield was captured by an infrared thermal imaging camera. The influence of adiabatic cooling efficiency was analyzed by different plate types, blow ratios and perforated percentages. In the experiment, flat panel and longitudinal corrugated heat-shield were adopted; the range of blow ratio was 0.5-3.0; the perforated percentage was 1.4%-3.7%. Results showed that, the film cooling efficiency of longitudinal corrugated heat-shield fluctuated with the fluctuation of corrugated plate structure and became larger than that of flat panel, while the film cooling efficiency of flat panel increased gradually along the way; with the increase of blow ratio, the film cooling efficiency increased gradually and reached to the maximum when the blow ratio increased to 3.0; the film cooling efficiency on the valley of the longitudinal corrugated surface was relatively higher than that on the wavy peak; the smaller the blow ratio, the more obvious the change of the film cooling efficiency with the fluctuation of corrugated plate; the film cooling efficiency changed and increased slowly along the high blow ratio (blow ratio of 2.0-3.0). As a whole, the film cooling efficiency increased gradually with the increase of the perforated percentage, and the film cooling efficiency at small perforated percentage (perforated percentage of 1.4%, 2.7%) was not much different, but on the leeward side of secondary flow, the film cooling with large perforated percentage was high.