Parameter optimization method of contra-rotating vertical axis wind turbine: Based on numerical simulation and response surface

Abstract

In recent years, the depletion of oil resources and increased in air pollution have become the two most serious challenges in the world. Therefore, the offshore vertical axis wind turbine (VAWT) has become a subject of increasing scholarly interest. However, the instability problem of VAWT has become an important reason that limits its continued development. Contra-rotating vertical axis wind turbines (CRVAWT) can improve the recovery efficiency of wind energy and improve the stability of wind turbines. However, the research on simulation analysis and parameter optimization of CRVAWT is not perfect, and further research is needed. This study first performed a numerical simulation of an isolated VAWT using STAR CCM + simulation software and compared the simulation results with wind tunnel tests to verify the accuracy of the model. After that, simulated and comparatively analyzed the proposed CRVAWT. The results indicated that the CRVAWT exhibits a lower power coefficient but better stability than the isolated VAWT. Then, simulations and analyses were conducted on the pitch angle, relative airfoil thickness, rotor spacing, and included angle of the CRVAWT. Finally, a four-parameter, three-level response surface optimization scheme was established using Design-Expert to optimize the blade parameters and obtain the optimal configuration of the contra-rotating wind turbine parameters. After optimization, the power coefficient (Cp) of the CRVAWT is 0.1837, which is 36.68% more than the Cp of pre-optimization and reaches 99.19% of the Cp of the isolated VAWT. And the total torque of the turbine is reduced by 96.96%, which provides a significant stability advantage.