Coupled effects of typical thermodynamic parameters on the flow and heat transfer in a high-pressure turbine outer ring with impingement-film composite cooling structure

Abstract

The research focused on a high-pressure turbine outer ring with an impingement-film composite cooling structure. Two methods of experimental measurements and numerical calculations were employed to investigate the outer ring cooling performance under typical thermodynamic parameters, such as the blowing ratio (M), temperature ratio (τ), and Mach number (Ma). The study aimed to elucidate the coupling effects between different thermodynamic parameters. It is revealed that increasing M led to improved cooling performance as it increased the cooling air flow rate and film hole outlet momentum. However, increasing Ma resulted in a less effective coverage of cooling air film on the outer ring, resulting in reduced cooling performance. Elevating the τ lowered the temperature of cooling air and outer ring but decreased the efficiency of cooling air utilization, leading to poorer cooling performance. The influence of M on the outer ring cooling property was independent of the τ, but M affected the magnitude of the change in cooling characteristics at different τ. A lower M enhanced τ effect on the cooling performance, while a higher M had the opposite effect. Increasing τ effectively mitigated the Ma impact on the outer ring cooling performance, especially at lower τ. Ma altered τ influence trend on the cooling performance. When 0.2 ≤ Ma < 0.6, increasing τ led to a decrease in cooling performance, but the extent of this decline decreased. When 0.6 < Ma ≤ 0.8, increasing τ resulted in an increase in cooling performance, but the improvement rate was moderated. Elevating the Ma enhanced M effect on the outer ring cooling performance. Specifically, when Ma is 0.2, increasing M from 0.7 to 3.0 elevates the outer ring overall cooling effectiveness from 0.3 to 0.45, reflecting a change of approximately 50 %. Similarly, when Ma is 0.8, an increase in M from 0.7 to 3.0 raises the overall cooling effectiveness from 0.1 to 0.35, indicating a more significant change of around 250 %.