Effect of Blade Pitch Angle on the Aerodynamic Characteristics of a Straight-bladed Vertical Axis Wind Turbine Based on Experiments and Simulations

Yanzhao Yang,Qing Song,Yanfeng Zhang,Zhiping Guo,Qing’An Li

doi:10.3390/en11061514

Abstract

The blade pitch angle has a significant influence on the aerodynamic characteristics of horizontal axis wind turbines. However, few research results have revealed its impact on the straight-bladed vertical axis wind turbine (Sb-VAWT). In this paper, wind tunnel experiments and CFD simulations were performed at the Sb-VAWT to investigate the effect of different blade pitch angles on the pressure distribution on the blade surface, the torque coefficient, and the power coefficient. In this study, the airfoil type was NACA0021 with two blades. The Sb-VAWT had a rotor radius of 1.0 m with a spanwise length of 1.2 m. The simulations were based on the k-ω Shear Stress Transport (SST) turbulence model and the wind tunnel experiments were carried out using a high-speed multiport pressure device. As a result, it was found that the maximum pressure difference on the blade surface was obtained at the blade pitch angle of β = 6° in the upstream region. However, the maximum pressure coefficient was shown at the blade pitch angle of β = 8° in the downstream region. The torque coefficient acting on a single blade reached its maximum value at the blade pitch angle of β = 6°. As the tip speed ratio increased, the power coefficient became higher and reached the optimum level. Subsequently, further increase of the tip speed ratio only led to a quick reversion of the power coefficient. In addition, the results from CFD simulations had also a good agreement with the results from the wind tunnel experiments. As a result, the blade pitch angle did not have a significant influence on the aerodynamic characteristics of the Sb-VAWT.

Highlights

Wind power technology, which utilizes the renewable clean energy, has been regarded as an important way to alleviate the energy crisis and environmental pollution [1,2,3,4,5]
Was investigated via wind tunnel experiments and CFD simulations, and the optimal blade pitch was investigated via wind tunnel experiments and CFD simulations, and the optimal blade pitch angle was identified
The conclusions can be summarized as follows: (1) Blade pitch angle effect on pressure distribution acting on single blade surface

Summary

Introduction

Wind power technology, which utilizes the renewable clean energy, has been regarded as an important way to alleviate the energy crisis and environmental pollution [1,2,3,4,5]. As shown, there are presently two main types of wind turbines: horizontal axis wind turbines (HAWTs) and vertical axis wind turbine (VAWTs) [6,7]. The large-type HAWT is very popular, but it is mainly installed in mountains, grasslands and oceans, where the infrastructure costs are very high. Straight-bladed vertical axis wind turbines (Sb-VAWTs) have been favored by global researchers due to their low production cost and insensitivity to high turbulence intensity in cities [11,12,13].

Objectives

Methods

Results

Conclusion