Aerodynamic optimization of bio-inspired micro-turbine blades based on Kriging surrogate model and particle swarm optimization

The compact dimensions of micro-turbine generators impose constraints on their energy conversion efficiency and power density. In this study, bio-inspired blades were developed by integrating fish-body profiles with tail-beating configurations, and an aerodynamic optimization framework coupling a Kriging surrogate model with particle swarm optimization (PSO) was proposed to explore the continuous design space with the objective of maximizing the power coefficient. Transient computational fluid dynamics (CFD) simulations were subsequently performed to evaluate the aerodynamic performance of the optimized blades. Among the investigated fish-inspired profiles, the shortfin-mako-inspired rotor achieves the highest peak power coefficient of 0.290, compared with 0.124 for the original rotor. Based on this profile, four geometric variables—the swing angle, front arc angle, rear arc angle, and trailing-edge radius—are further optimized. The optimal configuration [2°, 131°, 15°, 1.70 mm] achieves a CFD-evaluated peak power coefficient of 0.342 at TSR = 0.8, representing improvements of 17.9% over the shortfin-mako-inspired blade and 175.8% over the original rotor. Flow-field analysis shows that the optimized geometry strengthens the favorable pressure difference and interblade high-velocity flow while suppressing trailing-edge low-velocity and recirculation regions. The findings provide numerical evidence and design insights for the parametric optimization of bio-inspired micro-turbine blades.