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

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3196 ◽  
Author(s):  
Krzysztof Rogowski ◽  
Martin Otto Laver Hansen ◽  
Galih Bangga
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Point Of View ◽  
Power Coefficient ◽  
Navier Stokes ◽  
Vertical Axis Wind Turbine ◽  
Wide Range ◽  
Sst Turbulence Model ◽  
Lift And Drag ◽  
Blade Loads

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.

scholarly journals Performance analysis of a Darrieus-type wind turbine for a series of 4-digit NACA airfoils

2019 ◽  
Author(s):  
Krzysztof Rogowski ◽  
Martin Otto Laver Hansen ◽  
Galih Bangga
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Point Of View ◽  
Navier Stokes ◽  
Vertical Axis Wind Turbine ◽  
Wide Range ◽  
Sst Turbulence Model ◽  
Lift And Drag ◽  
Blade Loads

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 develop 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: the vortex model developed in Technical University of Denmark (DTU) and the extended version of the CFD code FLOWer at the University of Stuttgart (USTUTT). 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. The maximum rotor power coefficients are obtained at 0.5, which makes this impeller attractive from the point of view of further research. This work also addresses the issue of determining the aerodynamic performance of the rotor with various 4-digit NACA airfoils. The effect of two airfoil parameters, maximum airfoil thickness and maximum camber, on aerodynamic rotor performance is investigated. 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.

Performance Improvements for a Vertical Axis Wind Turbine by Means of Gurney Flap

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Yan Yan ◽  
Eldad Avital ◽  
John Williams ◽  
Jiahuan Cui
Keyword(s):  
Wind Turbine ◽  
Stokes Equations ◽  
Numerical Study ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Navier Stokes ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Performance Improvements ◽  
Gurney Flap

Abstract A numerical study was carried out to investigate the effects of a Gurney flap (GF) on the aerodynamics performance of the NACA 00 aerofoil and an associated three-blade rotor of a H-type Darrieus wind turbine. The flow fields around a single aerofoil and the vertical axis wind turbine (VAWT) rotor are studied using unsteady Reynolds-averaged Navier–Stokes equations (URANS). The height of GF ranges from 1% to 5% of the aerofoil chord length. The results show that the GF can increase the lift and lift-to-drag ratio of the aerofoil as associated with the generation of additional vortices near the aerofoil trailing edge. As a result, adding a GF can significantly improve the power coefficient of the VAWT at low tip speed ratio (TSR), where it typically gives low power production. The causing mechanism is discussed in detail, pointing to flow separation and dynamic stall delay.

Influence of Fixed Pitch Angle on the Performance of Small Scale H-Darrieus

2016 ◽  
Author(s):  
Teresa Parra-Santos ◽  
Diego J. Palomar Trullen ◽  
Armando Gallegos ◽  
Cristobal N. Uzarraga ◽  
Maria Regidor-Sanchez ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Pitch Angle ◽  
Stokes Equations ◽  
Vertical Axis ◽  
Navier Stokes ◽  
Small Scale ◽  
Vertical Axis Wind Turbine ◽  
Sst Turbulence Model ◽  
Set Up ◽  
Fixed Pitch

The performance of a Vertical Axis Wind Turbine (VAWT) is numerically analyzed. Influence of fixed pitch angle is studied to get tendencies on the characteristic curves. The set up corresponds with an H-Darrieus with three straight NACA airfoils attached to a vertical shaft. Two-dimensional, transient, Navier Stokes equations are solved with a Third-Order Muscl scheme using SIMPLE to couple pressure and velocity. At least three revolutions must be simulated to get the periodic behaviour. Transition SST turbulence model has been chosen based on literature. Pitch angles of −6° and −10° have been analyzed with Tip Speed Ratios ranging from 0.7 and 1.6. The pitch angle of −10° improves the performance of the wind turbine. Instantaneous and averaged power coefficients as well as detailed flow field around the airfoils are shown.

Numerical Investigation of Modified Bach Type Vertical Axis Wind Turbine

2016 ◽  
Vol 852 ◽  
pp. 551-557 ◽  
Author(s):  
R. Sarath Kumar ◽  
T. Micha Premkumar ◽  
Sivamani Seralathan ◽  
T. Mohan
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Flow Behaviour ◽  
Power Coefficient ◽  
Navier Stokes ◽  
Vertical Axis Wind Turbine ◽  
Navier Stokes Equation ◽  
Ansys Fluent ◽  
Improved Performance ◽  
And Performance

This study evaluates the performance and flow behaviour over the modified Bach type Vertical Axis Wind Turbine. A two dimensional unsteady state analysis is carried out in this study. The unsteady Reynolds Averaged Navier-Stokes equation and the turbulence equation corresponding to SST k-ω turbulence model are solved using commercial software ANSYS FLUENT 13. A grid independence study is performed to choose optimum mesh elements. The simulation is carried out and performance parameters like power coefficient and torque coefficient are calculated. The results are compared with the available experimental data for validation purpose and these matched with numerical values. An improved performance of around 37% Cp is observed for modified Bach type over simple Savonius rotor. Moreover, a brief analysis of flow behaviour over the rotor is studied.

scholarly journals Experimental Study of the Performance of a Novel Vertical-Axis Wind Turbine

2020 ◽  
Vol 10 (8) ◽  
pp. 2902
Author(s):  
James Agbormbai ◽  
Weidong Zhu
Keyword(s):  
Wind Turbine ◽  
Pressure Difference ◽  
Free Stream ◽  
Vertical Axis ◽  
Inviscid Flow ◽  
Momentum Equation ◽  
Power Coefficient ◽  
Navier Stokes ◽  
Vertical Axis Wind Turbine ◽  
Bernoulli’S Equation

Basic equations for estimating the aerodynamic power captured by the Anderson vertical-axis wind turbine (AVAWT) are derived from a solution of Navier–Stokes (N–S) equations for a baroclinic inviscid flow. In a nutshell, the pressure difference across the AVAWT is derived from the Bernoulli’s equation—an upshot of the integration of the Euler’s momentum equation, which is the N–S momentum equation for a baroclinic inviscid flow. The resulting expression for the pressure difference across the AVAWT rotor is plotted as a function of the free-stream speed. Experimentally determined airstream speeds at the AVAWT inlet and outlet, coupled with corresponding free-stream speeds, are used in estimating the aerodynamic power captured. The aerodynamic power of the AVAWT is subsequently used in calculating its aerodynamic power coefficient. The actual power coefficient is calculated from the power generated by the AVAWT at various free-stream speeds and plotted as a function of the latter. Experimental results show that at all free-stream speeds and tip-speed ratios, the aerodynamic power coefficient of the AVAWT is higher than its actual power coefficient. Consequently, the power generated by the AVAWT prototype is lower than the aerodynamic power captured, given the same inflow wind conditions. Besides the foregoing, the main purpose of this experiment is to investigate the technical feasibility of the AVAWT. This proof of concept enables the inventor to commercialize the AVAWT.

Novel Vertical-Axis Wind Turbine With Articulated Blading

2012 ◽  
Author(s):  
H. Jericha ◽  
E. Göttlich ◽  
T. Selic ◽  
W. Sanz
Keyword(s):  
Wind Turbine ◽  
Wind Direction ◽  
Vertical Axis ◽  
Bevel Gear ◽  
Power Coefficient ◽  
Return Flow ◽  
Vertical Axis Wind Turbine ◽  
Guide Vanes ◽  
Wide Range ◽  
Gear Box

In this work a novel vertical-axis wind turbine is presented which can catch a wide range of wind velocities at high efficiencies. The wind turbine consists of a rotatable horizontal platform, where three symmetric blades are arranged which rotate with half of the platform angular speed but in opposite direction relative to it. The rotation of the blades allows them to adapt to the varying angle of attack of the wind during one revolution of the platform. The important characteristic is the design feature that the blades are inclined outwards to the vertical axis of the platform by an angle of about 20 deg. The inclination leads to an increased circumferential velocity along the blade span, so that the increasing wind velocity with height can be better captured. Also the chord length of the blades increases with the spanwise position. In order to better utilize the wind flow, guide vanes can be arranged which increase the flow to those blades currently moving with the wind and in return flow can even give proper windshield. The articulated blades are connected to the horizontal platform via a special planetary bevel gear box, so that the relative rotational movement of them is controlled by the rotating platform, in fact a rotating gear box. This unit itself is connected to a generator thus producing electrical energy. The wind turbine can be tracked to a changed wind direction by means of rotating the stationary center bevel-gear wheel, which at given wind direction is then kept at constant position. In this paper the design of wind turbine is described in detail and the advantages of the novel vertical-axis turbine are discussed. First CFD investigations of a 2D section without guide vanes are presented. They show that maximum power can be achieved for a wide range of speed ratios. The calculated power coefficient is about 0.36, an interesting value for vertical-axis wind turbines.

scholarly journals Experimental Study of the Performance of A Novel Vertical Axis Wind Turbine

2019 ◽  
Author(s):  
James Agbormbai ◽  
Weidong Zhu
Keyword(s):  
Wind Turbine ◽  
Pressure Difference ◽  
Free Stream ◽  
Vertical Axis ◽  
Inviscid Flow ◽  
Momentum Equation ◽  
Power Coefficient ◽  
Navier Stokes ◽  
Wind Condition ◽  
Vertical Axis Wind Turbine

The basic equation for estimating the aerodynamic power captured by an Anderson Vertical Axis Wind Turbine (AVAWT) is a solution of the Navier-Stokes(N-S) equations for a baroclinic, inviscid flow. In a nutshell, the pressure difference across the AVAWT is derived from Bernoulli’s equation; an upshot of the integration of the N-S momentum equation for a baroclinic inviscid flow, Euler’s momentum equation. The resulting expression for the pressure difference across the AVAWT rotor is plotted as a function of freestream speed. Experimentally determined airstream speeds at the AVAWT inlet and outlet, coupled with corresponding freestream speeds are used in estimating the aerodynamic power captured. The aerodynamic power is subsequently used in calculating the aerodynamic power coefficient of the AVAWT. The actual power coefficient is calculated from the power generated by the AVAWT at various free stream speeds and plotted as a function of the latter. Experimental results show that, at all free stream speeds and tip speed ratios, the aerodynamic power coefficient is higher than the actual power coefficient of the AVAWT. Consequently, the power generated by the AVAWT prototype is lower than the aerodynamic power captured, given the same inflow wind condition.

Aerodynamic and aeroacoustic performance investigations on modified H-rotor Darrieus wind turbine

2021 ◽  
pp. 0309524X2110039
Author(s):  
Amgad Dessoky ◽  
Thorsten Lutz ◽  
Ewald Krämer
Keyword(s):  
Wind Turbine ◽  
High Speed ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
3D Models ◽  
Power Coefficient ◽  
Design Parameters ◽  
Second Phase ◽  
Vertical Axis Wind Turbine ◽  
Guide Vanes

The present paper investigates the aerodynamic and aeroacoustic characteristics of the H-rotor Darrieus vertical axis wind turbine (VAWT) combined with very promising energy conversion and steering technology; a fixed guide-vanes. The main scope of the current work is to enhance the aerodynamic performance and assess the noise production accomplished with such enhancement. The studies are carried out in two phases; the first phase is a parametric 2D CFD simulation employing the unsteady Reynolds-averaged Navier-Stokes (URANS) approach to optimize the design parameters of the guide-vanes. The second phase is a 3D CFD simulation of the full turbine using a higher-order numerical scheme and a hybrid RANS/LES (DDES) method. The guide-vanes show a superior power augmentation, about 42% increase in the power coefficient at λ = 2.75, with a slightly noisy operation and completely change the signal directivity. A remarkable difference in power coefficient is observed between 2D and 3D models at the high-speed ratios stems from the 3D effect. As a result, a 3D simulation of the capped Darrieus turbine is carried out, and then a noise assessment of such configuration is assessed. The results show a 20% increase in power coefficient by using the cap, without significant change in the noise signal.

Numerical Study of Pitch Angle on H-Type Vertical Axis Wind Turbine

2012 ◽  
Vol 499 ◽  
pp. 259-264
Author(s):  
Qi Yao ◽  
Ying Xue Yao ◽  
Liang Zhou ◽  
S.Y. Zheng
Keyword(s):  
Wind Turbine ◽  
Pitch Angle ◽  
Numerical Study ◽  
Vertical Axis ◽  
Azimuth Angle ◽  
Power Coefficient ◽  
Cfd Model ◽  
Vertical Axis Wind Turbine ◽  
Sliding Mesh ◽  
Mesh Technique

This paper presents a simulation study of an H-type vertical axis wind turbine. Two dimensional CFD model using sliding mesh technique was generated to help understand aerodynamics performance of this wind turbine. The effect of the pith angle on H-type vertical axis wind turbine was studied based on the computational model. As a result, this wind turbine could get the maximum power coefficient when pitch angle adjusted to a suited angle, furthermore, the effects of pitch angle and azimuth angle on single blade were investigated. The results will provide theoretical supports on study of variable pitch of wind turbine.

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