Numerical analysis of flow resistance and heat transfer in double wall configurations featuring solid and hollow pin-fins

With the aim of overcoming the inherent penalties of high flow resistance and limited heat transfer associated with conventional solid pin-fin double wall designs (DW-SPF), this study introduces a novel hollow pin-fin configuration (DW-HPF). A comparative analysis of the two configurations is performed via conjugate heat transfer simulations at M = 0.2–0.8. The DW-HPF de sign facilitates a bypass flow of the coolant, which diminishes the interaction strength between neighboring vortex pairs and consequently promotes superior film attachment. At M = 0.8, the DW-HPF achieves a 97.7% higher area-averaged film cooling effectiveness than the DW-SPF. While the hollow geometry somewhat compromises impingement cooling on the target plate, it introduces a dual-sided cooling effect on the pin-fin surfaces. Consequently, the overall surface-averaged Nusselt number of the DW-HPF surpasses that of the DW-SPF, registering a 15.4% improvement at M = 0.8. Furthermore, at the same blowing ratio, the DW-HPF demonstrates an 11.3% enhancement in overall cooling effectiveness and a substantial 49.3% increase in the discharge coefficient, underscoring its capacity for significant flow loss reduction. In essence, the proposed DW-HPF offers a synergistic balance between thermal and hydraulic performance, positioning it as a highly effective cooling solution for turbine blade hot spots.