叶片旋转转速和吹风比对涡轮外环双层壁结构阵列冲击冷却特性的影响研究

The heat transfer characteristics of array impingement jet in the shroud cavity with unsteady film effusion flow under the condition of rotating and sweeping turbine blades are numerically studied u-sing a coupled k-ω SST model and the sliding mesh method based on the unsteady Reynolds-average e-quation( URANS). In the composite impingement-film cooling structure of shroud, the jet holes and film holes are staggered, and the ratio of the jet-to-plate spacing to the jet hole diameter is 1. 25. The Strouhal numbers St are 2.35 and 3. 52( corresponding rotation speeds Ω are 10 000 r/min and 15 000 r/min), and the blowing ratios M are 0.5,1 and 1.5. The results show that the instantaneous mass flow at the inlet of the impingement hole changes due to the pressure fluctuation at the outlet of the film cooling hole caused by the blade rotating and sweeping effect,while the time-averaged mass flow remains almost unchanged; when the blowing ratio varies from 0. 5 to 1.5 ,the instantaneous and time-averaged impingement heat transfer characteristics of the target surface are enhanced with the increase of blowing ratio; at the same blowing ratio, the increase of the blade rotation speed has very little effect on the instantaneous and time-averaged heat transfer characteristics of the target surface.