Effect of curvature radius on leading edge cooling performance of double wall turbine blade

Double wall cooling is an efficient and promising cooling technology for turbine blade cooling. In this study, the effect of different curvature radius on the leading edge cooling performance of double wall turbine blade is explored. The heat transfer characteristics and flow structures of four kinds of double wall leading edge models with different curvature radius are thoroughly analyzed at different coolant inlet Reynolds numbers. The results indicate that the curvature radius of turbine blade significantly effects the cooling performance at the double wall turbine blade leading edge. The Nusselt number on the impingement surface of all leading edge models increases with the coolant inlet Reynolds number, exhibiting symmetry on both sides of the stagnation line. At a specified coolant inlet Reynolds number, the double wall leading edge featuring larger curvature radius achieve greater Nusselt number compared to those with smaller curvature radius. The laterally averaged cooling effectiveness of the double wall leading edge gradually decreases from the stagnation line along the mainstream direction. At low coolant inlet Reynolds number, the cooling effectiveness contours on both sides of the stagnation line are symmetrical. However, at high coolant inlet Reynolds number, the double wall leading edge with a larger curvature radius show pronounced asymmetries in cooling effectiveness on either side of the stagnation line. At the same coolant inlet Reynolds number, the double wall leading edge with a larger curvature radius exhibit a higher flow resistance coefficient. However, these configurations also demonstrate superior heat transfer performance at each coolant inlet Reynolds number. Specifically, when the inlet Reynolds number is 7.2×10⁴, the heat transfer performance of Case 3 is 58.2 % higher than that of Case 0.