针对高温透平叶片中弦区冷却,本文提出一种新型的无气膜孔管网冷却结构。该结构通过布置横向管道连接前缘冲击/气膜孔冷却、中弦区和尾缘劈缝冷却,并通过独立布置的外层竖向管道共同形成了管网冷却结构。该冷却结构可以应用于完整的叶片冷却系统中,具有中弦区无气膜孔、换热性能优越、温度分布均匀性好的有点,具有潜在的发展前景。利用数值模拟的方法,将该结构与典型含气膜孔的双层壁冷却结构进行对比,结果表明：该新型管网冷却结构相较双层壁冷却结构表面平均温度下降9.7K,同时表面温度分布均匀性更好。由于本文对该冷却结构的重点在于叶片中弦区,因此前缘和尾缘冷却性能相较于双层壁冷却有所降低,后续需要进一步对这些区域进行研究。此外,本文进一步研究了冷气雷诺数、温比变化的影响,发现雷诺数的增加可以降低管网冷却结构的叶片表面平均温度以及冷气进口总压,温比的降低导致叶片平均温度升高,同时需要优化内部结构以提升流动性能,降低流动阻力。

This paper proposes a new type of pipe network cooling structure without air film holes for the mid-chord region of high-temperature turbine blades. This structure connects the impingement/air film hole cooling for the leading edge, the middle chord region and the trailing edge split cooling through the arrangement of horizontal pipes, and together forms a pipe network cooling structure through independently arranged outer vertical pipes. This cooling structure can be applied to complete blade cooling systems, with advantages such as no gas film holes in the chord zone, superior heat transfer performance, and good temperature distribution uniformity. This structure has potential development prospects. By using numerical simulation methods, the structure was compared with a typical double-wall cooling structure with film holes. The results showed that the average surface temperature of the new pipeline cooling structure decreased by 9.7K compared to the double-wall cooling structure, and the uniformity of surface temperature distribution was better. Due to the focus of this article on the chord region of the blade, the cooling performance of the leading and trailing edges is worse compared to double-wall cooling. Further research is needed in the future. In addition, this article further studied the effects of changes in cold air Reynolds number and temperature ratio, and found that an increase in Reynolds number can reduce the average surface temperature of the cooling structure of the pipeline network and the total pressure of the cold air inlet. The decrease in temperature ratio leads to an increase in the average temperature of the blades. At the same time, it is necessary to optimize the internal structure to improve flow performance and reduce flow resistance.

TK474.7

国家自然科学基金项目