Heat transfer and flow characteristics of a novel double wall cooling design embedded by primitive-type triply periodic minimal surface structures

Abstract

This work proposes novel double wall cooling designs for modern gas turbines, where the traditional pin-fins are substituted by triply periodic minimal surface (TPMS) structures. A series of numerical simulations have been carried out to study the flow, heat transfer and temperature gradient (thermal stress for mechanical implications) behaviors for these novel configurations, which are validated against experimental data by infrared thermal imaging in a hot-gas wind tunnel. Results show that compared to the traditional pin–fin double wall structure, the internal convective heat transfer rate can be enhanced up to 57.9% by the TPMS design, which leads to an over 10% enhancement for overall cooling effectiveness. Proper design of TPMS structure could also reduce pressure loss, e.g., the P-B-0.6 configuration demonstrates a 2.7% reduction in pressure loss at the discussed condition. These advantages are correlated with the enlarged heat transfer area and the smooth pore-size curvatures that could decrease the turbulent dissipation loss. Further analysis revealed that TPMS designs could improve the temperature uniformity in the target surface, decrease the temperature gradient within the solid domains, and thereby reduce the thermal stress. The effect of porosity, TPMS type and mass flow ratio are further discussed.