Numerical study on small scale vertical axis wind turbine

Teresa Parra-Santos,Armando Gallegos,M. Veselý,Miguel A. Rodriguez,P. Dančová,Cristóbal N. Uzarraga

doi:10.1051/epjconf/201611402088

Teresa Parra-Santos, Armando Gallegos + Show 4 more

Open Access

https://doi.org/10.1051/epjconf/201611402088

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Abstract

The performance of a Vertical Axis Wind Turbine (VAWT) is numerically analyzed. The set-up is Hdarrieus with three straight blades airfoils NACA attached to a rotating vertical shaft. The wind turbine has solidity equals to the unity operating with wind velocity of 7 m/s. Influence of pitch angle is tested to get design tendencies. 2D, transient, Navier Stokes equations are solved using the code Ansys-Fluent. Conservation equations were solved with a Third-Order MUSCL scheme using SIMPLE to couple pressure and velocity. More than six revolutions must be simulated to get the periodic behavior. Two models of turbulence have been contrasted Realizable k-epsilon and Transition SST concluding the last one show more realistic flow features. Pitch angles of 0o, -6o and -10o have been tested with Tip Speed Ratios ranging from 0.7 and 1.6. The no null pitch angles improve the performance of the wind turbine. Instantaneous and averaged power coefficients as well as detailed flow field around the airfoils are showed.

Highlights

The computational model of an H- Darrieus wind turbine is built up using three air-foils NACA0015
The set-up is HDarrieus with three straight blades airfoils NACA attached to a rotating vertical shaft
The wind turbine has solidity equals to the unity operating with wind velocity of 7 m/s

Summary

Introduction

The computational model of an H- Darrieus wind turbine is built up using three air-foils NACA0015. Solidity of the wind turbine is the unity calculated as three times the ratio of chord versus diameter. Previous works involved with this research line were carried out using k-İ turbulence models and non-arm configuration. X The influence of the twist angle variation at the chord ends in symmetric airfoils NACA0015, [1]. Bearing in mind the Reynolds number is not very high, actual work uses the Transition SST turbulence model. Lanzafame states it performs well in this kind of applications, [5]. A secondary aim of this work is to analyze the influence of a fixed negative pitch angle, such as is proposed in [6]

Numerical model

Flow pattern at design conditions

Influence of the pitch angle

Conclusions