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.

Performance Evaluation of a 1 kW Variable Pitch-Straight Blade Vertical Axis Wind Turbine

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Muhammad Azfar Jamal ◽  
Owaisur Rahman Shah
Keyword(s):  
Wind Turbine ◽  
Natural Fiber ◽  
Research Work ◽  
Basalt Fiber ◽  
Weight Ratio ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Variable Pitch ◽  
Straight Blade

Abstract This research work represents a study of the design, analysis, and experimental study of a 1 kW variable pitch-straight blade vertical axis wind turbine (VAWT) using natural fiber reinforced composite. Wind turbine which is an emerging technology is of great interest for researchers nowadays. The VAWT was chosen for this study because of its numerous advantages over horizontal axis wind turbine (HAWT). A new concept of variable pitch was implemented by the introduction of a pitching mechanism associated with the turbine blades which helps the blade to maximize the generation of torque and power. For this purpose, the straight blade H-rotor design was chosen. The analytical calculations were performed for variable pitch and the fixed pitch blade followed by the computer aided design modeling of the rotor exhibiting the variable pitching mechanism. Computational fluid dynamics (CFD) analysis of the blade at the azimuth position of 0–360 deg was performed and the CFD results were imported into static structural module of ansys for the finite element analysis of the blade. The blade was 3D-printed at a reduced scale and tested in a wind tunnel for aerodynamic properties including lift, drag, and aerodynamic forces. A comparison was done between the analytical, software, and experimental values. Furthermore, basalt fiber which is a natural fiber was used as the material for the turbine blade and analysis was performed to obtain high strength to weight ratio of the composite material. The structure was analyzed under the damage tolerance study to determine for how long the structure can bear damage. The experimental results showed a good agreement with the analytical and numerical values. The introduction of the variable pitching mechanism resulted in an increase in the cumulative torque as compared with the fixed pitching mechanism which in turn enhanced the resulting power.

Variable pitch control for vertical-axis wind turbines

2018 ◽  
Vol 42 (2) ◽  
pp. 128-135 ◽  
Author(s):  
S Horb ◽  
R Fuchs ◽  
A Immas ◽  
F Silvert ◽  
P Deglaire
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Three Dimensional ◽  
Vertical Axis ◽  
Two Dimensional ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Variable Pitch ◽  
Pitch Control

NENUPHAR aims at developing the next generation of large-scale floating offshore vertical-axis wind turbine. To challenge the horizontal-axis wind turbine, the variable blade pitch control appears to be a promising solution. This article focuses on blade pitch law optimization and resulting power and thrust gain depending on the operational conditions. The aerodynamics resulting from the implementation of a variable blade pitch control are studied through numerical simulations, either with a three-dimensional vortex code or with two-dimensional Navier-stokes simulations (two-dimensional computational fluid dynamics). Results showed that the three-dimensional vortex code used as quasi-two-dimensional succeeded to give aerodynamic loads in very good agreement with two-dimensional computational fluid dynamics simulation results. The three-dimensional-vortex code was then used in three-dimensional configuration, highlighting that the variable pitch can enhance the vertical-axis wind turbine power coefficient ( Cp) by more than 15% in maximum power point tracking mode and decrease it by more than 75% in power limitation mode while keeping the thrust below its rated value.

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%.

scholarly journals Predicted and measured performance of a vertical axis wind turbine with passive variable pitch compared to fixed pitch

2016 ◽  
Vol 41 (1) ◽  
pp. 74-90 ◽  
Author(s):  
Brian K Kirke ◽  
Benoit Paillard
Keyword(s):  
Wind Turbine ◽  
Control Mechanism ◽  
Vertical Axis ◽  
Dynamics Simulation ◽  
Maximum Efficiency ◽  
Vertical Axis Wind Turbine ◽  
Actual Performance ◽  
Variable Pitch ◽  
Starting Torque ◽  
Fixed Pitch

The performance of a 5-m diameter Darrieus vertical axis wind turbine was predicted using both a double multiple streamtube model and a two-dimensional unsteady Reynolds-averaged Navier–Stokes computational fluid dynamics simulation with constant rotational speed for a series of operational points. The actual performance was measured in both fixed and variable pitch modes. The aims were (1) to compare starting torque and peak efficiency in fixed and variable pitch modes and (2) to test an overspeed control mechanism. Starting torque was approximately three times higher in variable pitch mode and the maximum efficiency on some runs was significantly higher. The overspeed control mechanism functioned consistently as designed. Thus, variable pitch was shown to overcome two major disadvantages of normal fixed pitch vertical axis wind turbines, self-starting and overspeed control. Discrepancies between the predicted and measured results showed the importance of accurately assessing parasitic drag losses and the need for three-dimensional simulation to give reliable performance predictions.

scholarly journals Modeling, Simulation, Hardware Implementation of a Novel Variable Pitch Control for H-Type Vertical Axis Wind Turbine

2015 ◽  
Vol 66 (5) ◽  
pp. 264-269 ◽  
Author(s):  
Liqun Liu ◽  
Chunxia Liu ◽  
Xuyang Zheng
Keyword(s):  
Wind Turbine ◽  
Control Method ◽  
Vertical Axis ◽  
Utilization Efficiency ◽  
Vertical Axis Wind Turbine ◽  
Variable Pitch ◽  
Pitch Control ◽  
Start Up ◽  
Variable Pitch Control ◽  
Fixed Pitch

Abstract It is well known that the fixed pitch vertical axis wind turbine (FP-VAWT) has some disadvantages such as the low start-up torque and inefficient output efficiency. In this paper, the variable pitch vertical axis wind turbine (VP-VAWT) is analyzed to improve the output characteristics of FP-VAWT by discussing the force of the six blade H type vertical axis wind turbine (VAWT) under the stationary and rotating conditions using built the H-type VAWT model. First, the force of single blade at variable pitch and fixed pitch is analyzed, respectively. Then, the resultant force of six blades at different pitch is gained. Finally, a variable pitch control method based on a six blade H type VP-VAWT is proposed, moreover, the technical analysis and simulation results validate that the variable pitch method can improve the start-up torque of VAWT, and increase the utilization efficiency of wind energy, and reduce the blade oscillation, as comparable with that of FP-VAWT.

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.

Aerodynamic Analysis for Camber Effect in Vertical Wind Turbine System

2011 ◽  
Author(s):  
Jinwook Kim ◽  
Dohyung Lee ◽  
Junhee Han ◽  
Sangwoo Kim
Keyword(s):  
Numerical Simulation ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Low Wind Speed ◽  
Wind Turbine System ◽  
Physical Features ◽  
The Ideal

The Vertical Axis Wind Turbine (VAWT) has advantages over Horizontal Axis Wind Turbine (HAWT) that it allows less chance to be degraded independent of wind direction and turbine can be operated even at the low wind speed. The objective of this study is to analyze aerodynamics of the VAWT airfoil and investigate the ideal shape of airfoil, more specifically cambers. The analysis of aerodynamic characteristics with various cambers has been performed using numerical simulation with CFD software. As the numerical simulation discloses local physical features around wind turbine, aerodynamic performance such as lift, drag and torque are computed for single airfoil rotation and multiple airfoil rotation cases. Through this study more effective airfoil shape is suggested based vortex-airfoil interaction studies.

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