Small wind turbines: A numerical study for aerodynamic performance assessment under gust conditions

2018 ◽  
Vol 121 ◽  
pp. 123-132 ◽  
Author(s):  
L. Menegozzo ◽  
A. Dal Monte ◽  
E. Benini ◽  
A. Benato
Keyword(s):  
Performance Assessment ◽  
Wind Turbines ◽  
Numerical Study ◽  
Aerodynamic Performance ◽  
Small Wind Turbines

scholarly journals Characterization of aerodynamic performance of ducted wind turbines: A numerical study

Wind Energy ◽  
2019 ◽  
Vol 22 (12) ◽  
pp. 1655-1666 ◽  
Author(s):  
Vinit V. Dighe ◽  
Gael Oliveira ◽  
Francesco Avallone ◽  
Gerard J. W. Bussel
Keyword(s):  
Wind Turbines ◽  
Numerical Study ◽  
Aerodynamic Performance

Computational Investigation of a Shrouded Vertical Axis Wind Turbine

2016 ◽  
Author(s):  
K. Vafiadis ◽  
H. Fintikakis ◽  
I. Zaproudis ◽  
A. Tourlidakis
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Urban Areas ◽  
Numerical Study ◽  
Flow Analysis ◽  
Vertical Axis ◽  
Green Energy ◽  
Vertical Axis Wind Turbine ◽  
Wide Range ◽  
Small Wind Turbines

In urban areas, it is preferable to use small wind turbines which may be integrated to a building in order to supply the local grid with green energy. The main drawback of using wind turbines in urban areas is that the air flow is affected by the existence of nearby buildings, which in conjunction with the variation of wind speed, wind direction and turbulence may adversely affect wind energy extraction. Moreover, the efficiency of a wind turbine is limited by the Betz limit. One of the methods developed to increase the efficiency of small wind turbines and to overcome the Betz limit is the introduction of a converging – diverging shroud around the turbine. Several researchers have studied the effect of shrouds on Horizontal Axis Wind Turbines, but relatively little research has been carried out on shroud augmented Vertical Axis Wind Turbines. This paper presents the numerical study of a shrouded Vertical Axis Wind Turbine. A wide range of test cases, were examined in order to predict the flow characteristics around the rotor, through the shroud and through the rotor – shroud arrangement using 3D Computational Fluid Dynamics simulations. The power output of the shrouded rotor has been improved by a factor greater than 2.0. The detailed flow analysis results showed that there is a significant improvement in the performance of the wind turbine.

STUDY ON AERODYNAMIC PERFORMANCE OF THE BIONIC AIRFOIL BASED ON THE SWALLOW'S WING

2013 ◽  
Vol 13 (06) ◽  
pp. 1340022 ◽  
Author(s):  
WEIJUN TIAN ◽  
FANGYUAN LIU ◽  
QIAN CONG ◽  
YURONG LIU ◽  
LUQUAN REN
Keyword(s):  
Wind Tunnel ◽  
Wind Turbines ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Aerodynamic Performance ◽  
Wind Tunnel Tests ◽  
Small Wind Turbines ◽  
Aerodynamic Performances ◽  
Drag Ratio ◽  
Bionic Airfoil

This paper demonstrates the design of the airfoil of small wind turbines, the bionic airfoil was inspired by the morphology of the swallow's extended wing. The wind tunnel tests on the bionic and standard airfoils NACA4412 were conducted, and the aerodynamic performances of the airfoils were numerically investigated. The results show that the bionic airfoil has better aerodynamic performance, the lift coefficient and lift-drag ratio are larger than those of the NACA4412; with the angle of attack increases, both the bionic and standard airfoils stall, but the stall characteristics of the bionic airfoil are better.

scholarly journals Multi-element ducts for ducted wind turbines: A numerical study

2019 ◽  
Author(s):  
Vinit V. Dighe ◽  
Francesco Avallone ◽  
Ozer Igra ◽  
Gerard van Bussel
Keyword(s):  
Viscous Flow ◽  
Wind Turbines ◽  
Deflection Angle ◽  
Numerical Study ◽  
Aerodynamic Performance ◽  
Viscous Effects ◽  
Duct Geometry ◽  
Total Thrust ◽  
Flap Deflection ◽  
Radial Gap

Abstract. Multi-element ducts are used to improve the aerodynamic performance of ducted wind turbines (DWTs). Steady-state, two-dimensional computational fluid dynamics (CFD) simulations are performed for a multi-element duct geometry, consisting of a duct and a flap; goal is to evaluate the effects on the aerodynamic performance of the radial gap length and the deflection angle of the flap. Solutions from inviscid and viscous flow calculations are compared. It is found that increasing the radial gap length results in an augmentation of the total thrust generated by the DWT, whereas a larger deflection angle has an opposite effect. A reasonable to good agreement is seen between the inviscid and viscous flow calculations, except for multi-element duct configurations characterized by large flap deflection angles. The viscous effects become stronger at large flap deflection angles, and the inviscid calculations are incapable to take into account this phenomenon.

scholarly journals Multi-element ducts for ducted wind turbines: a numerical study

2019 ◽  
Vol 4 (3) ◽  
pp. 439-449 ◽  
Author(s):  
Vinit V. Dighe ◽  
Francesco Avallone ◽  
Ozer Igra ◽  
Gerard van Bussel
Keyword(s):  
Viscous Flow ◽  
Wind Turbines ◽  
Deflection Angle ◽  
Numerical Study ◽  
Aerodynamic Performance ◽  
Viscous Effects ◽  
Duct Geometry ◽  
Total Thrust ◽  
Flap Deflection ◽  
Radial Gap

Abstract. Multi-element ducts are used to improve the aerodynamic performance of ducted wind turbines (DWTs). Steady-state, two-dimensional computational fluid dynamics (CFD) simulations are performed for a multi-element duct geometry consisting of a duct and a flap; the goal is to evaluate the effects on the aerodynamic performance of the radial gap length and the deflection angle of the flap. Solutions from inviscid and viscous flow calculations are compared. It is found that increasing the radial gap length results in an augmentation of the total thrust generated by the DWT, whereas a larger deflection angle has an opposite effect. Reasonable to good agreement is seen between the inviscid and viscous flow calculations, except for multi-element duct configurations characterized by large flap deflection angles. The viscous effects become stronger at large flap deflection angles, and the inviscid calculations are incapable of taking this phenomenon into account.

Design of low noise airfoil with high aerodynamic performance for use on small wind turbines

2010 ◽  
Vol 53 (1) ◽  
pp. 75-79 ◽  
Author(s):  
Taehyung Kim ◽  
Seungmin Lee ◽  
Hogeon Kim ◽  
Soogab Lee
Keyword(s):  
Wind Turbines ◽  
Aerodynamic Performance ◽  
Low Noise ◽  
Small Wind Turbines

scholarly journals EXPERIMENTAL EVALUATION OF THE AERODYNAMIC PERFORMANCE OF SMALL WIND TURBINES CONFECTIONED IN 3D PROTOTYPING

2016 ◽  
Vol 15 (2) ◽  
pp. 15
Author(s):  
S. O. Garré ◽  
A. V. Paula ◽  
J. L. R. Luz ◽  
T. D. J. Vecina ◽  
A. P. Petry
Keyword(s):  
Velocity Profile ◽  
Wind Turbines ◽  
Experimental Evaluation ◽  
Angular Position ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Power Coefficient ◽  
Small Wind Turbines ◽  
Static Torque

This paper presents the experimental evaluation of the aerodynamic performance of two small wind turbines models with five blades in the Aerodynamic Tunnel Professor Debi Pada Sadhu. The models were confectioned on a reduced scale using 3D prototyping, the first one was designed using the blade element method, assuming the power coefficient of Betz, named Optimal Blade Betz (OBB) and the second is modified from the first one, named Optimal Blade Betz Modified (OBBM). The velocity distribution in the cross section of the tunnel was determined with the aid of a Pitot tube before the evaluation of the equipment. With the known tunnel velocity profile, the static torque of the prototypes were determined with the use of a digital torquemeter coupled to the machine axis, which recorded the readings for the speed range of 1 m/s to 9.88 m/s. Also with the torquemeter, were evaluated the influence of the angular position of the blades in the measured torque. The blades were designed allowing vary their angular position in the hub, thus changing the angle of attack, and by consequence, the torque produced. A photo tachometer was employed to measure the rotation of the model in free spin. With the experimental data, the curves of static torque and angular velocity were determined as a function of incident speed. Through experimental determination of the incident velocity profile and the velocity profile in the aerodynamic wake of each turbine, the variation of the amount of momentum of the outflow was evaluated, and so the power extracted by the rotor in free rotation. This study aims to contribute to the design of a real small wind turbine, informing the aerodynamic characteristics of the equipment that can be constructed with this layout. The experimental results demonstrate good approximation for torque and power to the results obtained by evaluation by element of the blade method. The turbine constructed with Optimal Betz Blades presented static torque 17.8% higher than constructed with the Modified Blades and extracted 22% more power from the air outflow.

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