Enhancing the Performance of an H-Darrieus Hydrokinetic Turbine Through Geometric Optimization of an External Channel

The transition to sustainable energy systems requires the development of efficient hydrokinetic technologies to increase the reliability and competitiveness of renewable energy generation. Vertical-axis H-Darrieus turbines can improve their performance through impeller channels or external flow guidance devices that modify the local mass flow distribution around the rotor. This work introduces a systematic geometric optimization framework that quantitatively evaluates the combined effect of key channel design parameters on turbine performance by employing response surface methodology (RSM) to quantify the influence of two geometric parameters of an impeller channel—specifically, the deflection angle (β) and the channel length (H)—on the turbine power coefficient (Cp). This approach allows for the identification of nonlinear interactions between geometric variables, which have not been explicitly addressed in previous research on impeller channels in H-Darrieus turbines. An experimental design with thirteen treatments was implemented, and numerical simulations were performed using Computational Fluid Dynamics (CFD) in ANSYS FLUENT®. Statistical analysis of the RSM model showed that both β and H have significant effects (p