燃气轮机一级透平动静叶交互作用的气膜非定常特性及泛冷却效应:Part 1-静叶栅

Unsteady Characteristic of Film Cooling and Phantom Cooling on the First Stage of a Gas Turbine:Part 1-Vane Cascade

采用三维非定常数值模拟计算某重型燃气轮机第一级透平的全气膜冷却特性,探讨级环境下静叶表面与静叶端壁及动叶表面与动叶平台的气膜非定常特性及泛冷却效应。燃气轮机泛冷却是指燃气轮机透平冷却气体出流在非设计位置所引起的附加效果。该部分工作包含两部分内容,其中第一部分关注级环境下静叶全气膜及燃烧室与静叶间的环缝密封出流在静叶端壁上的气膜覆盖,以及环缝密封出流在下游静叶栅中所形成的泛冷却效应。结果表明,在时均来流条件下,静叶表面及端壁气膜冷却效率分布非定常特征并不明显;燃烧室与静叶环缝密封出流在端壁上形成气膜覆盖,同时在静叶吸力面轴向Z/C>0.5和叶高S/H<10%区域形成泛冷却效应,且泛冷却效率随着环缝密封流量的增大而呈指数关系快速上升,设计工况下最大泛冷却效率达0.11。

3-D URANS （unsteady Reynolds average N-S equations simulation） is implemented to investigate the film cooling performance on the first stage of a gas turbine, discussing the unsteady characteristics of film cooling and phantom cooling in the stage environment. The phantom cooling is defined as the adjunct effect on the off-design position derived from the upstream cooling discharges. The present work includes two parts of content. The part one focuses on the unsteady film cooling characteristic of the vane and endwall on the first stage, and the phantom cooling derived from seal ejection of the slot between combustor and vane. The results of film cooling effectiveness distribution on the vane surface and endwall are steady generally with time-average inlet conditions. The seal ejection of the slot between combustor and vane produces film cooling coverage on the endwall, and simultaneously generates phantom cooling on the zone of suction side, between axial direction Z/C 〉 0.5 and spanwise S/H 〈 10%. Furthermore, the phantom cooling effectiveness ascends signi- ficantly as the mass flux of the seal ejection increases, the maximum effectiveness is up to 0.11 in the operating condition.