Résumé:
This study focuses on the redesign and optimization of the three-
dimensional geometry of a micro horizontal-axis wind turbine (HAWT) blade
using Response Surface Methodology (RSM). The geometric variation of two key
design parameters, chord length and twist angle, is mathematically modeled using
a fourth-degree and second-degree polynomial, respectively. The optimization
framework is based on eight input parameters that define the initial blade
configuration.
To evaluate aerodynamic performance and structural integrity, a
comprehensive comparative analysis is conducted between the initial and
optimized blade designs using Computational Fluid Dynamics (CFD) and Blade
Element Momentum (BEM) methods. The CFD simulations utilize the Reynolds-
Averaged Navier-Stokes (RANS) equations with the k-ω SST turbulence model to
capture complex flow phenomena and predict aerodynamic efficiency. The
optimization process is implemented using a Multi-Objective Genetic Algorithm
(MOGA) coupled with a non-parametric regression (NPR) metamodel, enabling
the automated selection of the most efficient blade design.
Performance assessments of the turbine rotor are carried out using the
open-source software QBlade, with results compared against CFD predictions
across various Tip Speed Ratio (TSR) values. The optimized blade demonstrates
significant improvements, yielding a 15% and 12.53% increase in power coefficient
for CFD and QBlade analyses, respectively, at a design TSR of 3. Compared to the
baseline blade, the optimized design exhibits superior aerodynamic characteristics,
including enhanced lift generation, reduced flow separation, and improved
efficiency across all TSR values.
Furthermore, a detailed three-dimensional flow analysis, incorporating
pressure distribution and limiting streamlines on both blade surfaces, confirms the
optimization objectives. The results highlight a notable reduction in flow
separation zones and a subsequent increase in rotor torque. Additionally, structural
safety considerations reveal a 37% improvement in starting operability at lower
wind speeds, contributing to enhanced overall performance and operational
reliability.
