Flow structure and heat transfer characteristics in turbine blade trailing-edge cooling channels with upright and curved Reuleaux triangular pin-fins

As the core hot-section component of gas turbines for energy conversion, turbine blades play a critical role in the overall performance of gas turbine units. However, the operating temperature of advanced gas turbines has far exceeded the temperature resistance limit of blade materials, and the cooling effect of conventional cylindrical pin-fins on the turbine blade trailing edge has gradually failed to meet the design requirements. This makes the trailing edge highly prone to thermal ablation, which further impairs gas turbine performance. Therefore, it is urgent to develop a more efficient trailing-edge cooling configuration to ensure the safe operation of turbine blades. For this purpose, this paper systematically investigates the flow and heat transfer performance of seven Reuleaux pin-fin configurations in turbine blade trailing-edge cooling channels under stationary conditions via numerical simulation, with the Reynolds number ( Re ) ranging from 7000 to 40,000. The investigated configurations cover four cross-sectional profiles (circular baseline, 1.8-order Reuleaux, 1.6-order Reuleaux, and standard Reuleaux profile) and five curved surface designs (convex +2, convex +4, concave -2, concave -4, and upright baseline). Compared with the conventional cylindrical pin-fin baseline, the upright pin-fin with standard Reuleaux profile achieves a 15.03% increase in normalized Nusselt number ( Nu ), and the 1.8-order Reuleaux pin-fin delivers a 4.13% improvement in thermal-hydraulic performance factor ( TPF ). Among the curved surface configurations, the convex +4 design realizes a maximum Nu increment of 23.88%, while the concave -4 design achieves a 58.86% reduction in friction factor ( f ) and an 18.18% increase in comprehensive TPF . The Nu of convex configurations presents an accelerated growth trend with the increase of Re . This study clarifies the flow and heat transfer mechanism of Reuleaux pin-fins, and can provide critical guidance for the design of high-efficiency pin-fin cooling structures for advanced gas turbine blades.