Numerical and experimental investigation of flow and heat transfer in jet impingement and pin-fin cooling of turbine blade trailing edge

Trailing-edge regions of aero-engine turbine blades are exposed to high thermal loads, while the available cooling space is severely limited. Conventional rib–pin-fin passages can enhance internal heat transfer. However, spanwise coolant decay, uneven cooling near the blade tip and root, and strong flow interaction between cooling regions remain unresolved. This study developed a rib–jet impingement–pin-fin coupled cooling configuration for turbine trailing-edge cooling. Unlike previous studies that mainly examined individual cooling elements or isolated geometric parameters, the present work investigated the combined effects of spanwise jet spacing ratio S _ex /D _e (2–4) jet-to-pin-fin distance ratio H _e /D (2–5), and impingement location (R1–R2). Transient liquid crystal (TLC) thermography and numerical simulations based on the SST k–ω turbulence model were performed over Re = 20,000–60,000. At Re = 40,000 , the final optimized configuration increased the area-averaged Nusselt number (Nu _avg ) from 160 to 298, corresponding to an enhancement of approximately 86% relative to the baseline rib–pin-fin passage. It also reduced localized low-heat-transfer regions near the channel end regions and improved wall heat-transfer uniformity. The impingement baffle weakened flow coupling between the ribbed and pin-fin regions. It also produced smoother spanwise attenuation of the static pressure coefficient (Cp) than the baseline configuration. These results indicate that turbine trailing-edge cooling can be improved by coordinating jet development distance, spanwise jet coverage, and impingement location, rather than by increasing local jet intensity alone.