Designing manufacturable high performance rotor blades for micro wind
turbines through cambered plate airfoil optimization
Abstract
Conventional methods for manufacturing rotor blades, such as composite
construction and die casting, are hindered by high costs due to
expensive molds, while 3D printing often results in poor quality or high
production costs with unfavorable cost-per-part scaling. Moreover,
conventional airfoil designs perform poorly at Reynolds numbers below
100,000, necessitating larger rotors. This becomes especially
problematic in wind tunnel studies, where multiple rotors must fit
within a single wind tunnel for wake or multirotor research,
significantly increasing both building costs and wind tunnel
requirements. To address these challenges, this study develops
high-performance rotor blades for micro wind turbines that are
aerodynamically efficient under low Reynolds number conditions and easy
to manufacture. Using cambered plate airfoils, the optimization process
employed a class shape transformation and seventh-degree Bernstein
polynomials. Aerodynamic performance was analyzed using XFOIL, with
evaluations conducted at Reynolds numbers of 30,000, 40,000, and 50,000
to ensure robust performance across realistic operating scenarios. The
iterative optimization employed both single-objective and (genetic)
multi-objective algorithms, targeting both aerodynamic efficiency and
manufacturability. The blade tested with the optimized MB-LR2-7.5
airfoil exhibited superior performance in wind tunnel tests, closely
matching Blade Element Momentum (BEM) simulations. This research
highlights the potential of cambered plate airfoils to improve micro
wind turbine performance while maintaining ease of manufacturing, with
potential applications in UAVs, drone propellers, and HVAC systems. The
findings advance the understanding of aerodynamic optimization in low
Reynolds number environments, paving the way for more efficient and
cost-effective rotor designs.