Conjugate heat transfer and fluid flow analysis on printable double-wall effusion cooling with internal topology-optimized TPMS structures

Double-wall effusion is a highly efficient cooling technique in modern gas turbine blades. This study uses topology optimization infilled with triply periodic minimal surface structures (TPMS) to design high-performance internal cooling structures, improving cooling effectiveness and mitigating thermal stress for the double-wall channel. The flow, heat transfer, and static structural characteristics of the topology-optimized TPMS model are compared with the results of the smooth and circular pin fin configurations. Results show that the optimized model provides a uniform flow inside the channel and the effusion holes, reducing the jet lift-off and keeping the coolant attached to the effusion wall. Within the blowing ratios of 0.5–1.7, the optimized model improves impingement heat transfer by 9.5 %–12.5 % compared to the pin fin configuration. The averaged overall cooling effectiveness is also 4.2 %–4.6 % with lower pressure loss. The thermal stress and total deformation are evenly distributed and show 22.9 % and 12.0 % lower than the pin fin model. Moreover, a 3D laser scanning microscope and high-resolution CT scan are used to evaluate the manufacturability of the optimized sample, printed by laser powder bed fusion with an actual gas turbine blade scale. The results benefit the fabrication improvement for next-generation gas turbine blades.