scholarly journals Optimization of Symmetrical Airfoils of the Darrieus Vertical Axis Wind Turbine

2020 ◽  
Vol 55 (3) ◽  
Author(s):  
Hadi Sutanto ◽  
Chin-Tu Lu ◽  
Hodik Chaiyadi
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Angle Of Attack ◽  
Vertical Axis ◽  
Coefficient Of Performance ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Lift And Drag ◽  
Lift And Drag Coefficient ◽  
The Impact

The vertical-axis wind turbine has an advantage over the horizontal-axis wind turbine because of its structural simplicity due to the independence of motion in wind direction. This article describes a new idea on how to develop the Darrieus vertical-axis wind turbine by modifying the angle of attack and adding airfoils on the wind turbine. The wind turbine has a symmetrical airfoil of NACA 0012 with three-double blade configurations to optimize the performance of the vertical shaft wind turbine. A computational fluid dynamics technique was used to understand the impact of variations of wind velocity on the angle of attack and additional distance of airfoil in turbulence intensity based on the contour of wind velocity passing the wind turbine. Using this method, the authors showed that the results of the study in turn with the variation of wind velocity, different angle of attack and additional distance of airfoil have an effect on the values of lift and drag coefficient. The highest value of the coefficient of lift is 4.1, followed by the coefficient of drag which is 0.79 at 0.3 m with the angle of attack at -4o, the wind velocity is 9.428 m/s and the result of the highest torque is 0.57 Nm which has a coefficient of performance of 1.3%.

Development and Application of a Simulation Tool for Vertical and Horizontal Axis Wind Turbines

2013 ◽  
Author(s):  
David Marten ◽  
Juliane Wendler ◽  
Georgios Pechlivanoglou ◽  
Christian Navid Nayeri ◽  
Christian Oliver Paschereit
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Horizontal Axis ◽  
Vertical Axis Wind Turbine ◽  
First Case ◽  
Horizontal Axis Wind Turbines ◽  
Lift And Drag ◽  
The Impact

A double-multiple-streamtube vertical axis wind turbine simulation and design module has been integrated within the open-source wind turbine simulator QBlade. QBlade also contains the XFOIL airfoil analysis functionalities, which makes the software a single tool that comprises all functionality needed for the design and simulation of vertical or horizontal axis wind turbines. The functionality includes two dimensional airfoil design and analysis, lift and drag polar extrapolation, rotor blade design and wind turbine performance simulation. The QBlade software also inherits a generator module, pitch and rotational speed controllers, geometry export functionality and the simulation of rotor characteristics maps. Besides that, QBlade serves as a tool to compare different blade designs and their performance and to thoroughly investigate the distribution of all relevant variables along the rotor in an included post processor. The benefits of this code will be illustrated with two different case studies. The first case deals with the effect of stall delaying vortex generators on a vertical axis wind turbine rotor. The second case outlines the impact of helical blades and blade number on the time varying loads of a vertical axis wind turbine.

EXPERIMENTAL AND NUMERICAL EVALUATION OF PERFORMANCE OF A VARIABLE PITCH VERTICAL AXIS WIND TURBINE

2021 ◽  
pp. 1-14
Author(s):  
Owaisur Rahman Shah ◽  
Azfar Jamal ◽  
Talha Irfan Khan ◽  
Usama Waleed Qazi
Keyword(s):  
Wind Turbine ◽  
Azimuthal Angle ◽  
Research Work ◽  
Vertical Axis ◽  
Experimental Results ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Variable Pitch ◽  
Lift And Drag ◽  
Fixed Pitch

Abstract The research work depicts the study of the comparison of a 1kW Fixed Pitch Vertical Axis Wind Turbine (VAWT) and a Variable Pitch VAWT via analytical, numerical and experimental results. Being an emerging technology, wind turbine is becoming a source of attraction for the researchers. The VAWT in comparison to the Horizontal Axis Wind Turbine (HAWT), has shown numerous benefits. The fundamental purpose of this work is to maximize the output power and output torque of the wind turbine. For achieving an improved output, a novel and unique mechanism, termed as pitching mechanism, is employed that follows the variable pitch concept. The mathematical modelling was done for the straight blade variable pitch VAWT as well as for the fixed rotor. The four bar mechanism was developed, to execute the variable pitch mechanism, and implemented in the form of the CAD model. A scaled down 3D Model of the rotor was manufactured using 3D printing technique. The aerodynamic forces such as lift and drag were measured upon the rotor as per the testing on the rotor in the wind tunnel. CFD simulations were run for the fixed pitch as well as the variable pitch rotor. The transient analysis was performed for the azimuthal angle ranging from 0 to 360 degrees and for a pitch angle varying from +25 to-25 degrees in ANSYS software. The comparative study was undertaken, keeping in view the analytical, simulation and experimental results. A worthy agreement was observed between analytical, software and experimental results and a promising increase in power and torque was observed due the introduction of the variable pitch mechanism. The power produced by the variable pitch design showed a significant increase in the power production as compared to the fixed pitch design. The numerical and experimental values of cp for the variable pitch design were quite comparable.

A New Structure for Low Speed Wind Turbine in Built-Up Areas

2013 ◽  
Vol 860-863 ◽  
pp. 314-318
Author(s):  
Feng Ji ◽  
Xiao Jian Feng ◽  
Dong Liang Wang
Keyword(s):  
Growth Rate ◽  
Wind Turbine ◽  
Wind Velocity ◽  
Wind Turbines ◽  
Residential Building ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Low Speed

Traditional wind turbines are difficulty to work well in built-up areas due to wind conditions of low speed, turbulence and frequent changing direction. A long-term wind observation work has been done to understand the characteristics of urban wind by installing a small weather station on the balcony at top floor of a residential building. Based on the observation results, a new structure for low speed wind turbine in built-up areas was designed. This structure can be used for either horizontal axis wind turbine or vertical axis wind turbine. Some mesh models were established to simulate the effect through CFD software. In this structure, growth rate of wind velocity is about 1.25 times; wind turbulence converts to laminar; and yawing angel of turbine motor shafts neednt change any more. Prototype testing draws better conclusions: growth rate of wind velocity is more than 1.4 times. Therefore, traditional wind turbines can work well in built-up areas through this new structure.

scholarly journals Performance Augmenting of a Vertical Axis Wind Turbine using Adaptable Convergent Ducting System

2018 ◽  
Vol 14 (3) ◽  
pp. 141-148
Author(s):  
Abdullateef A. Jadallah ◽  
Sahar R. Farag ◽  
Jinan D. Hamdi
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Vertical Axis ◽  
Coefficient Of Performance ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Tip Speed Ratio ◽  
Vertical Axis Wind Turbines ◽  
Inlet Angle

Developments are carried out to enhance the performance of vertical axis wind turbines (VAWT). This paper studies the performance of the ducted wind turbine with convergent duct (DAWT). Basically, the duct technique is utilized to provide the desired wind velocity facing the turbine. Methodology was developed to estimate the decisive performance parameter and to present the effect of the convergent duct with different inlet angles. The ducted wind turbine was analyzed and simulated using MATLAB software and numerically using ANSYS-Fluent 17.2. Result of both approaches were presented and showed good closeness for the two cases of covering angles 12  and 20 respectively. Results also showed that the convergent duct with an inlet angle 12   and 20  improved the coefficient of performance at a specified tip speed ratio by 25.8% and 33.33% respectively in the productivity of wind turbine.  

scholarly journals Performance Analysis and Optimization of a Vertical-Axis Wind Turbine with a High Tip-Speed Ratio

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 996
Author(s):  
Liang Li ◽  
Inderjit Chopra ◽  
Weidong Zhu ◽  
Meilin Yu
Keyword(s):  
Wind Turbine ◽  
Pitch Angle ◽  
Angle Of Attack ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Aerodynamic Loads ◽  
Tip Speed Ratio ◽  
Aerodynamic Model ◽  
Lift And Drag

In this work, the aerodynamic performance and optimization of a vertical-axis wind turbine with a high tip-speed ratio are theoretically studied on the basis of the two-dimensional airfoil theory. By dividing the rotating plane of the airfoil into the upwind and downwind areas, the relationship among the angle of attack, azimuth, pitch angle, and tip-speed ratio is derived using the quasi-steady aerodynamic model, and aerodynamic loads on the airfoil are then obtained. By applying the polynomial approximation to functions of lift and drag coefficients with the angle of attack for symmetric and asymmetric airfoils, respectively, explicit expressions of aerodynamic loads as functions of the angle of attack are obtained. The performance of a fixed-pitch blade is studied by employing a NACA0012 model, and influences of the tip speed ratio, pitch angle, chord length, rotor radius, incoming wind speed and rotational speed on the performance of the blade are discussed. Furthermore, the optimization problem based on the dynamic-pitch method is investigated by considering the maximum value problem of the instantaneous torque as a function of the pitch angle. Dynamic-pitch laws for symmetric and asymmetric airfoils are derived.

Effect of Solidity on Performance of Vertical Axis Wind Turbine Using Constant Chord Reynolds Number

2021 ◽  
Author(s):  
Anirudh P ◽  
Ratna Kishore Velamati ◽  
Srinath K S ◽  
Unnikrishnan D
Keyword(s):  
Reynolds Number ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
Coefficient Of Performance ◽  
Vertical Axis Wind Turbine ◽  
Number Range ◽  
Turbine Performance ◽  
The Impact

Abstract The demand for wind turbines has increased ever since fossil fuels showed signs of quick depletion. Among wind turbines, Vertical Axis Wind Turbine (VAWT) is compact, produces less noise, is omnidirectional, resilient to turbulent flow, and is easy to maintain. The power generated by a VAWT is a function of a non-dimensional geometric parameter known as solidity (s), which is a function of turbine diameter (D), blade chord (c) and the number of blades (n). The present work analyses the impact of solidity (0.12 and 0.18) as a complete non-dimensional parameter on wind turbine performance. Each parameter of solidity is varied, keeping any one of the parameters constant and numerically studied for its performance across a range of tip speed ratios (TSR). For each solidity, six different combinations of VAWT geometric parameters were analyzed. In all the cases, the chord Reynolds number is kept constant. CFD simulation was performed on the Darrieus H-type (NACA0018 airfoil) VAWT. Two dimensional (2D) computational domains are used to study the effect on the turbine’s performance as the solidity studied is less than 0.4. Unsteady Reynolds-Averaged Navier-strokes (URANS) equation is used to solve the CFD model using ANSYS Fluent 19.1 with 4-equation transition SST k-ω for turbulence modelling. The comprehensive study of the turbine performance keeping the turbine operation within a constant Re number range shows the Coefficient of Performance (Cp) overlaps for a given solidity.

Calculating the aerodynamics of vertical axis wind turbines

2012 ◽  
Vol 34 (3) ◽  
pp. 169-184 ◽  
Author(s):  
Hoang Thi Bich Ngoc
Keyword(s):  
Wind Turbine ◽  
Incidence Angle ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Velocity Triangle ◽  
Relationship Of ◽  
The Relationship

Vertical axis wind turbine technology has been applied last years, very long after horizontal axis wind turbine technology. Aerodynamic problems of vertical axis wind machines are discussible. An important problem is the determination of the incidence law in the interaction between wind and rotor blades. The focus of the work is to establish equations of the incidence depending on the blade azimuth, and to solve them. From these results, aerodynamic torques and power can be calculated. The incidence angle is a parameter of velocity triangle, and both the factors depend not only on the blade azimuth but also on the ratio of rotational speed and horizontal speed. The built computational program allows theoretically selecting the relationship of geometric parameters of wind turbine in accordance with requirements on power, wind speed and installation conditions.

Power Experimental Optimization of Horizontal Axis Wind Turbine

2020 ◽  
Vol 13 (3) ◽  
pp. 438-443
Author(s):  
Sadek Ameziane ◽  
Abdesselem Chikhi ◽  
Mohammed Salah Aggouner
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Energy System ◽  
Spatial Filter ◽  
Complex Model ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Detailed Model ◽  
Continuous Current ◽  
Mechanical Sensors

Background: The presented article is a contribution to the realization of a wind emulator based on a continuous-current machine. The development of this topic focuses on the modeling of a vertical axis wind turbine, a DC motor with independent excitation and its control via a chopper. Methods: To carry out this work, we have studied and designed the electronic and mechanical sensors as well as a command implemented on the dSPACE DS1103 system. Results: The main purpose of this work is related, on one hand, to the control of the motor turbine by imposing the wind profile and on the other hand generate the command of the implanted MPPT. The experimental results obtained showed the great performances which characterize this improved wind energy system. Conclusion: Finally, a wind turbine with variable speed is a system having a complex model; however, a detailed model of the interaction between the wind and the aero-turbine is useful to understand certain phenomena such as rotational sampling or the spatial filter.

Experimental Study of Vertical Axis Wind Turbine with Wind Speed Self-Adapting

2012 ◽  
Vol 215-216 ◽  
pp. 1323-1326
Author(s):  
Ming Wei Xu ◽  
Jian Jun Qu ◽  
Han Zhang
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Velocity ◽  
Vertical Axis ◽  
Maximum Power ◽  
The Self ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Opening And Closing

A small vertical axis wind turbine with wind speed self-adapting was designed. The diameter and height of the turbine were both 0.7m. It featured that the blades were composed of movable and fixed blades, and the opening and closing of the movable blades realized the wind speed self-adapting. Aerodynamic performance of this new kind turbine was tested in a simple wind tunnel. Then the self-starting and power coefficient of the turbine were studied. The turbine with load could reliably self-start and operate stably even when the wind velocity was only 3.6 m/s. When the wind velocity was 8 m/s and the load torque was 0.1Nm, the movable blades no longer opened and the wind turbine realized the conversion from drag mode to lift mode. With the increase of wind speed, the maximum power coefficient of the turbine also improves gradually. Under 8 m/s wind speed, the maximum power coefficient of the turbine reaches to 12.26%. The experimental results showed that the new turbine not only improved the self-starting ability of the lift-style turbine, but also had a higher power coefficient in low tip speed ratio.

Coupled Dynamics of a Vertical Axis Wind Turbine (VAWT) With Active Blade Pitch Control on a Semi-Submersible Floater

2018 ◽  
Author(s):  
Ebert Vlasveld ◽  
Fons Huijs ◽  
Feike Savenije ◽  
Benoît Paillard
Keyword(s):  
Wind Turbine ◽  
Wind Velocity ◽  
Vertical Axis ◽  
Power Production ◽  
Mooring Line ◽  
Vertical Axis Wind Turbine ◽  
Coupled Dynamics ◽  
Low Frequencies ◽  
Pitch Control ◽  
Thrust And Torque

A vertical axis wind turbine (VAWT) typically has a low position of the center of gravity and a large allowable tilt angle, which could allow for a relatively small floating support structure. Normally however, the drawback of large loads on the VAWT rotor during parked survival conditions limits the extent to which the floater size can be reduced. If active blade pitch control is applied to the VAWT, this drawback can be mitigated and the benefits can be fully utilized. The coupled dynamics of a 6 MW VAWT with active blade pitch control supported by a GustoMSC Tri-Floater semi-submersible floater have been simulated using coupled aero-hydro-servo-elastic software. The applied blade pitch control during power production results in a steady-state thrust curve which is more comparable to a HAWT, with the maximum thrust occurring at rated wind velocity. During power production, floater motions occur predominantly at low frequencies. These low frequency motions are caused by variations in the wind velocity and consequently the rotor thrust and torque. For the parked survival condition, it is illustrated that active blade pitch control can be used to effectively reduce dynamic load variations on the rotor and minimize floater motions and mooring line tensions.

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