Horizontal-axis propeller hydrokinetic turbine optimization by using the response surface methodology: Performance effect of rake and skew angles

Abstract

ABSTRACT: The design of a horizontal-axis propeller hydrokinetic turbine (HPHT) depends on several geometric parameters affecting its hydrodynamic efficiency which is measured through the power coefficient (CP ). In this study, a 1 kW turbine with 1.6 m of rotor diameter (D) was used as the prototype to know the relationship between the CP and the turbine design parameters, such as the skew (φ) and rake (γ) angles. A full-factorial design of experiments, as a response surface methodology technique, and computational fluid dynamics simulation were used to determine the significance of the factors considered and their interaction in the maximization of the response variable (CP ). A 3D computational domain in ANSYS Fluent software and the k-ω SST turbulence model were utilized, for the unsteady flow simulations. Under optimal design conditions, i.e., when φ and γ were equal to 13.30° and -18.06°, respectively, the highest CP was 0.4571. For these optimal values, a scaled model with 0.24 m of diameter was numerical and experimentally studied and the findings were compared. A good agreement was found between the numerical results regarding the lab-scale turbine and the experimental data for the CP values obtained as a function of the tip speed ratio.