PDF(Sci-hub)
Abstract：
To meet the economic requirements of power output, the increased inlet temperature of modern gas turbines is above the melting point of the material. Therefore, high-efficient cooling technology is needed to protect the blades from the hot mainstream. In this study, film cooling was investigated in a simplified channel. A bulge located upstream of the film hole was numerically investigated by analysis of the film cooling effectiveness distribution downstream of the wall. The flow distribution in the plate channel is first presented. Comparing with a case without bulge, different cases with bulge heights of 0.1d, 0.3d and 0.5d were examined with blowing ratios of 0.5 and 1.0. Cases with 1% mist injection were also included in order to obtain better cooling performance. Results show that the bulge configuration located upstream the film hole makes the cooling film more uniform, and enhanceslateral cooling effectiveness. Unlike other cases, the configuration with a 0.3d-height bulge shows a good balance in improving the downstream and lateral cooling effectiveness. Compared with the case without mist at M = 0.5, the 0.3d-height bulge with 1% mist injection increases lateral average effectiveness by 559% at x/d = 55. In addition, a reduction of the thermal stress concentration can be obtained by increasing the height of the bulge configuration.
摘要：
为满足功率输出的经济性要求,现代燃气轮机的入口温度高于材料的熔点。因此,需要高效的冷却技术来保护叶片免受热的主流影响。在这项研究中,在简化的通道中研究了薄膜冷却。通过分析壁下游的薄膜冷却效率分布，对位于薄膜孔上游的凸起进行了数值研究。首先介绍板通道中的流量分布。与没有凸起的情况相比，凸起高度为0.1d的不同情况，用0.5和1.0的吹气比检查0.3d和0.5d。为了获得更好的冷却性能，还包括了注入1％雾的情况。结果表明，位于薄膜孔上游的凸起结构使冷却薄膜更加均匀，并增强横向冷却效率。与其他案件不同,具有0.3d高度凸起的配置在改善下游和横向冷却效率方面表现出良好的平衡。与M=0.5时没有雾的情况相比，注射1％雾的0.3d高度凸起在x/d=55时将侧向平均有效性提高了559%。此外,可以通过增加凸起结构的高度来降低热应力集中。
