Performance Analysis of a H-Darrieus Wind Turbine for a Series of 4-Digit NACA Airfoils

Krzysztof Rogowski,Galih Bangga,Martin Otto Laver Hansen

doi:10.3390/en13123196

Abstract

The purpose of this paper is to estimate the H-Darrieus wind turbine aerodynamic performance, aerodynamic blade loads, and velocity profiles downstream behind the rotor. The wind turbine model is based on the rotor designed by McDonnell Aircraft Company. The model proposed here consists of three fixed straight blades; in the future, this model is planned to be developed with controlled blades. The study was conducted using the unsteady Reynolds averaged Navier–Stokes (URANS) approach with the k-ω shear stress transport (SST) turbulence model. The numerical two-dimensional model was verified using two other independent aerodynamic approaches: a vortex model and the extended version of the computational fluid dynamics (CFD) code FLOWer. All utilized numerical codes gave similar result of the instantaneous aerodynamic blade loads. In addition, steady-state calculations for the applied airfoils were also made using the same numerical model as for the vertical axis wind turbine (VAWT) to obtain lift and drag coefficients. The obtained values of lift and drag force coefficients, for a Reynolds number of 2.9 million, agree with the predictions of the experiment and XFOIL over a wide range of angle of attack. A maximum rotor power coefficient of 0.5 is obtained, which makes this impeller attractive from the point of view of further research. Research has shown that, if this rotor were to work with fixed blades, it is recommended to use the NACA 1418 airfoil instead of the original NACA 0018.

Highlights

The purpose of these investigations was to analyze the impact of two parameters of 4-digit
National Advisory Committee for Aeronautics (NACA) series airfoils, maximum airfoil thickness and maximum camber on the aerodynamic blade load, on aerodynamic efficiency of the H-Darrieus rotor and velocity distribution downstream behind the rotor. Both aerodynamic blade loads and velocity profiles downstream behind the rotor depend on these two geometrical airfoil parameters, as well a tip speed ratio
Different numerical methods of fluid dynamics were used in this work, and, for computational fluid dynamics (CFD), the k-ω

Summary

Introduction

A French aviation engineer, patented a wind turbine rotor capable of operating independently of the wind direction and in adverse weather conditions. The Darrieus wind turbine, having a rotor with a vertical rotation axis, is often used to convert wind energy into electric energy. The Darrieus wind turbine is composed of several curved blades attached to a vertical rotating shaft. Darrieus suggested other possible solutions for turbines with a vertical rotation axis. One of them was H-rotor (rotor in H pattern), known as “H-bar”. The rotor of this type consists of long straight blades, which are usually fastened to the tower by means of horizontal struts

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