Multiphysics topology optimization method for regenerative cooling channels integrating structural-thermal-hydraulic performance

With the development of high-speed and lightweight aircraft, cooling channels must dissipate intense heat while maintaining structural integrity under severe thermo-mechanical loads. Current design methods mainly focus on thermal-hydraulic performance, often neglecting load-bearing capacity, which can lead to stress concentrations and premature failure. To overcome this limitation, this study proposes a multiphysics topology optimization framework that concurrently integrates structural stiffness, strength, thermal resistance, and flow resistance in cooling channel design. A density-based approach combines a multi-layer 2D conjugate heat transfer model with a projected 3D mechanical analysis, thus avoiding stiffness singularity in 2D channel analysis while enabling efficient evaluation of temperature, flow, compliance, and stress. Numerical examples under various design conditions demonstrate that incorporating load-bearing performance significantly alters channel layouts compared to thermal-hydraulic-only designs, eliminating stress-concentrating features. The optimized designs can increase stiffness by up to 27.41% and reduce maximum stress by 17.44%, while effectively managing thermal performance. These results validate the proposed method as a robust tool for designing cooling channels that meet combined structural-thermal-hydraulic requirements, providing an effective method to improve high-performance aerospace thermal management systems.