Evaluation of Sealing and Film-Cooling Performance According to Coolant Injection Conditions in the Secondary Flow Path of an F-Class Gas Turbine Combustor

Leakage flow at the SEV combustor liner and first-stage vane hub interface can degrade sealing, disrupt purge flows, and increase thermal loads on hot-gas-path components. This study numerically investigated the effects of coolant injection angle and blowing ratio (M) on leakage suppression and film-cooling performance in the secondary flow path of an F-class gas turbine using ANSYS CFX. The computational domain encompassed the main-flow passage, secondary flow path, seal-sheet structure, and a simplified vane leading-edge model. Sealing characteristics was analyzed via cross-sectional flow structures and temperature distributions, while cooling performance was evaluated using adiabatic film-cooling effectiveness on the liner endwall and vane hub. Under horizontal injection, coolant impinged on the vane hub, lost momentum, and allowed hot mainstream gas to recirculate into the secondary passage. Conversely, changing the injection angle to 30° effectively suppressed hot-gas ingestion, reducing the internal temperature by 300–400 °C. Furthermore, increasing the blowing ratio from 0.5 to 2.0 at a 30° angle strengthened fluidic sealing, lowering temperatures by roughly 300–500 °C. While the liner endwall achieved maximum cooling effectiveness at M = 1.0, the vane hub showed continuous improvement up to M = 2.0. Ultimately, combined optimization of injection angle and blowing ratio is essential for ensuring the thermal integrity of liner–vane interface components.