Cooling scheme from phantom cooling effect using vane film coolant on the endwall surface

This study employs numerical simulations based on the SST k-ω-transition model to investigate the endwall phantom cooling effect induced by the coolant from the vane pressure surface film cooling holes in a turbine cascade, systematically examining the effects of key parameters including the relative distance from the hole row end to the endwall, compound angle, mass flow ratio, and hole row position. Results demonstrate that increasing the compound angle significantly enhances the phantom cooling coverage area and average effectiveness compared to non-angled configurations, while higher mass flow ratio and upstream-positioned cooling holes expand the phantom cooling region and improve overall cooling performance. The relative distance notably affects upstream cooling behavior, while its influence on downstream regions remains relatively limited. Based on these findings, a double-jet film cooling configuration is proposed from the perspective of phantom cooling enhancement. This configuration achieves a 38.6% increase in film cooling effectiveness on the vane pressure surface and an 18.8% improvement in phantom cooling effectiveness on the endwall, with only a 0.35% increase in the cascade energy loss coefficient, highlighting the superior performance of the proposed design. This study not only advances the fundamental understanding of phantom cooling but also provides a practical and efficient cooling scheme for turbine applications.