Investigation on the influence of structural parameters on the performance of double wall turbine blade leading edge

This paper investigates the effects of structural parameters on the cooling performance and structural strength of double wall turbine blade leading edge. A one-way coupling method was employed to perform fluid-thermal-structural analysis on the double wall leading-edge structure. First, a detailed conjugate heat transfer analysis was performed to explore the effects of impingement hole diameter, pin fin diameter, and film hole diameter on Nusselt number, cooling effectiveness, and flow resistance coefficient. Subsequently, the temperature field obtained from the heat transfer analysis was interpolated and coupled into structural strength model to analyze the impact of structural parameters on Von Mises stress. The findings reveal that impingement hole diameter has a pronounced impact on the Nusselt number of the impingement target surface, while film hole diameter significantly influences cooling effectiveness. Specifically, within a diameter range of 0.75 to 1.00, the area-averaged Nusselt number at a diameter of 0.75 is 26.54% higher than that at 1.00. At a blowing ratio of 2.5, a film hole diameter of 1.00 offers highest cooling effectiveness and the lowest pressure loss coefficient. The maximum Von Mises stress tends to increase when the temperature field boundary condition is applied to the double wall leading edge, although the thermal expansion of the outer wall can partially offset the compressive stress. Moreover, the average Von Mises stress increases with larger impingement and film hole diameters but decreases with larger pin fin diameters. Considering the cooling performance and structural strength, within the parameter range studied, the double-wall leading edge structure has better comprehensive performance under high blowing ratio when the impingement hole diameter, pin fin diameter and film hole diameter are 0.75, 1.00 and 1.00 respectively.