Influence of structural parameters on the cooling and creep performance of double-wall turbine blade considering surface curvature

In this study, a comprehensive numerical investigation is conducted to assess the influence of curvature radius on the thermal-mechanical performance of double-wall turbine blade structures. A coupled conjugate heat transfer computational fluid dynamics (CFD) and structural analysis approach is employed, where temperature fields obtained from computational fluid dynamics simulations are interpolated into structural models for creep behavior analysis. Four geometric parameters are optimized using a four-factor, five-level orthogonal design independently at each of four curvature radii ranging from 10mm to 60mm. The results demonstrate that increasing curvature radius promotes smoother geometric transitions and enhanced structural deformation coordination, thereby reducing stress concentrations and improving cooling effectiveness. Multi-objective optimization using response surface methodology achieves simultaneous minimization of structural stresses and maximization of cooling performance. The optimized configurations yield improvements including up to 10.59% enhancement in cooling effectiveness, 14.86% reduction in von Mises equivalent stress, 18.52% decrease in creep strain, and 14.38% reduction in maximum shear stress. This research establishes a high-fidelity multidisciplinary optimization framework that systematically incorporates surface curvature effects, providing practical guidelines for balancing aerodynamic, thermal, and structural requirements in double-wall turbine blade configurations and offering theoretical support for design strategies aiming to enhance blade longevity under extreme operating conditions.