Abstract
Under the inspiration of polar coordinates, a novel parametric modeling and optimization method for Savonius wind turbines was proposed to obtain the highest power output, in which a quadratic polynomial curve was bent to describe a blade. Only two design parameters are needed for the shape-complicated blade. Therefore, this novel method reduces sampling scale. A series of transient simulations was run to get the optimal performance coefficient (power coefficient C p) for different modified turbines based on computational fluid dynamics (CFD) method. Then, a global response surface model and a more precise local response surface model were created according to Kriging Method. These models defined the relationship between optimization objective Cp and design parameters. Particle swarm optimization (PSO) algorithm was applied to find the optimal design based on these response surface models. Finally, the optimal Savonius blade shaped like a “hook” was obtained. Cm (torque coefficient), Cp and flow structure were compared for the optimal design and the classical design. The results demonstrate that the optimal Savonius turbine has excellent comprehensive performance. The power coefficient Cp is significantly increased from 0.247 to 0.262 (6% higher). The weight of the optimal blade is reduced by 17.9%.
Highlights
In recent years, the gradually exhausting non-renewable energy resources and economic viability stimulate the development of renewable energy technology
The performance comparison of optimum configuration with conventional Savonius rotor showed an increase of 24.12%
Kriging response surface model was established in feasible region
Summary
The gradually exhausting non-renewable energy resources and economic viability stimulate the development of renewable energy technology. Savonius turbines are suitable for many scenarios, such as the small and medium-sized distributed power generation [1]. Main advantages of Savonius wind turbines can be described as follows: high starting up and full operation moment; operate in a wide range of wind conditions; simple construction with low cost; low noise emission and stable performance [2,3,4]. Altan et al [5] and Tian et al [2] have explained the work principle of a Savonius rotor by analyzing the main flows around the turbine. Relatively low efficiency of Savonius turbines is a great limitation. Different efforts are directed towards finding a better design for Savonius turbines, which will improve its performance. Some previous studies have suggested many different modified methods to obtain the optimal Savonius turbine. The “optimal” means that the Savonius wind turbine has its highest
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