Study of film cooling performance of a support strut heat shield with multiple slot hole structures

As the turbine outlet temperature and the temperature of the afterburner continue to increase, it is necessary to cool and protect the heat shield of support strut in the exhaust system. This study investigates the film cooling characteristic of support strut heat shield in turbine exhaust systems, Utilizing Pressure Sensitive Paint (PSP) technology, experimental measurements of cooling effectiveness(η) were conducted under variable conditions of blowing ratios (M = 0.5, 0.75, 1.0, 1.25, and 1.4) and density ratios (DR = 1.0, 1.5, 2.0, and 2.6). The flow performance of the film cooling structure on the guide shield was also analyzed by numerical method with a steady state Navier-Stokes equation. The results demonstrate that slot holes, particularly the configuration of slot hole B, significantly enhance the film cooling effectiveness of the guide shield compared to that of the fan-shaped film hole structure. Furthermore, the cooling effectiveness of the leading edge of the guide shield with a slot hole B configuration is increased by 48.83 % than that of the slot hole A configuration at M = 1.0 and DR = 1.5. At the same time, the film cooling effectiveness of slot B is increased respectively by 60.97 % and 39.05 % on pressure surface and suction surface compared with that of fan-shaped hole. Additionally, numerical simulations concerning the behind flow field of fan-shaped hole and slot hole B near the guide shield revealed that the reason of the greater cooling effectiveness in slot B is the lower kidney vortex intensity and wider spanwise coverage. These findings suggest that slot hole B can provide significant thermal protection on guide strut shields, offering a promising solution for advanced heat shield cooling designs.