Aerothermal characteristics of thin double-wall effusion cooling systems with novel slot holes and cellular architectures for gas turbines

Double-wall effusion cooling system is a promising cooling solution for next-generation gas turbines. Thinning the blade wall can bring the coolant closer to the hot stream, thereby enhancing overall cooling effectiveness. However, a thin blade wall creates film cooling holes with a short length-to-diameter ratio, which increases jet-crossflow mixing and reduces coolant attachment, inevitably degrading film cooling performance. Herein, we constructed a new thin double-wall effusion cooling system by integrating novel short slot holes for better coolant attachment and triply periodic minimal surface (TPMS) based cellular architectures for improved internal heat transfer. The effects of wall thickness, film hole shape, and internal turbulators configurations were numerically studied. Adiabatic and overall film cooling effectiveness, vortex structures, and aerodynamics loss were comprehensively assessed. The results demonstrate that the novel slot hole significantly improves the overall film cooling effectiveness under thin wall conditions by enhancing the attachment of kidney vortices to walls. Notably, compared to the short fan-shaped hole (scheme B), the novel slot hole (scheme C) shows an improvement in the averaged overall cooling effectiveness of over 20% and a reduction in the total pressure loss coefficient by 60%. Furthermore, three TPMS-based cellular architectures produce similar overall film cooling effectiveness and reduction of total pressure loss coefficient in the range of 0.57-0.81 and 23%-53%, respectively. This work provides guidance for designing thin double-wall effusion cooling systems for next-generation gas turbines. © 2023 Elsevier Masson SAS. All rights reserved.