Separated Flow Control of Small Horizontal-Axis Wind Turbine Blades Using Dielectric Barrier Discharge Plasma Actuators

Hikaru Aono,Hiroaki Fukumoto,Makoto Sato,Yoshiaki Abe,Taku Nonomura,Kozo Fujii

doi:10.3390/en13051218

Abstract

The flow control over the blades of a small horizontal-axis wind turbine (HAWT) model using a dielectric barrier discharge plasma actuator (DBD-PA) was studied based on large-eddy simulations. The numerical simulations were performed with a high-resolution computational method, and the effects of the DBD-PA on the flow fields around the blades were modeled as a spatial body force distribution. The DBD-PA was installed at the leading edge of the blades, and its impacts on the flow fields and axial torque generation were discussed. The increase in the ratios of the computed, cycle-averaged axial torque reasonably agreed with that of the available experimental data. In addition, the computed results presented a maximum of 19% increase in the cycle-averaged axial torque generation by modulating the operating parameters of the DBD-PA because of the suppression of the leading edge separation when the blade’s effective angles of attack were relatively high. Thus, the suppression of the leading edge separation by flow control can lead to a delay in the breakdown of the tip vortex as a secondary effect.

Highlights

Wind turbines convert the kinematic energy of wind into electrical energy
The results in the cases with flow control show a suppression of the leading edge separation near the tip region, which leads to very weak vortex-flow interactions between the tip vortex and the separated flow from the leading edge
This is the secondary effect of the flow control of dielectric barrier discharge plasma actuator (DBD-PA), and it may play a role in the reduction of sound generation

Summary

Introduction

Wind turbines convert the kinematic energy of wind into electrical energy. A horizontal-axis wind turbine (HAWT) is a common type of wind turbine, and usually consists of three main components, namely, a rotor, generator, and surrounding structure. The rotor includes the blades, where the aerodynamics of each blade have been sufficiently studied for more efficient and stable power generation [1]. The flow around wind turbine blades is sometimes separated due to the environmental flow around them, and this separation often causes unsteadiness and vibrations. Flow separation is one of the main issues that disrupts the stable and robust power generation. In the current study, we investigate the control of the separated flow over wind turbine blades using a dielectric barrier discharge plasma actuator (DBD-PA).

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