scholarly journals The effect of gurney flap on flow characteristics of vertical axis wind turbine

2020 ◽  
Vol 34 (14n16) ◽  
pp. 2040107
Author(s):  
Taurista Perdana Syawitri ◽  
Yu-Feng Yao ◽  
Jun Yao ◽  
Budi Chandra
Keyword(s):  
Wind Turbine ◽  
Lift Coefficient ◽  
Flow Characteristics ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Trailing Edge ◽  
Eddy Simulation ◽  
Moment Coefficient ◽  
Gurney Flap

Recently, the Gurney Flap (GF) has been used to improve the performance of Horizontal Axis Wind Turbine (HAWT) by enhancing its lift coefficient. Compared to HAWT, research on GF application for Vertical Axis Wind Turbine (VAWT) is very limited. Moreover, most works studied a GF geometry attached to the trailing edge of a stationary airfoil, without considering the rotating effect experienced by VAWT. For this reason, a three-straight-bladed VAWT rotating blade with GF is studied by transient RANS simulation together with a stress-blended eddy simulation (SBES) turbulence model to investigate the GF height effect and the flow characteristics near the blade trailing edge. Results have shown that by introducing the blade rotating, an optimum GF height is found to be 3% of the blade chord, slightly higher than 2% chord in a stationary airfoil case. In addition, the presence of GF can delay deep stall of VAWT blades, thus eliminating negative instantaneous moment coefficient and improving the turbine performance.

Numerical Investigation on Vertical Axis Wind Turbine in Search for an Efficient Design

2015 ◽  
Author(s):  
Mosfequr Rahman ◽  
Mohammad Bashar ◽  
Gustavo Molina ◽  
Valentin Soloiu ◽  
Travis Salyers
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Lift Coefficient ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Technological Advancement ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
The World ◽  
Alternative Sources

The continuous improvement of this world is based on technological advancement. And the technological advancement is directly related to the utilization of energy. The demand of energy is creeping up every day due to increase of population, industrial and agricultural advancement. But the conventional energy sources are becoming limited which is ultimately making them more expensive. In addition to this, everyone is concerned about global climate change. This whole scenario is pushing the world to find the alternative sources of energy. Alternative sources involve natural phenomena such as sunlight, wind, tides, plant growth, and geothermal heat. Solar and Wind power are the most popular among the various sources of renewable energy. Wind alone can fulfill most of the energy requirement of the world by its efficient conversion in to energy. Though Horizontal Axis Wind Turbine (HAWT) is more popular but needs high wind speed to extract energy from the wind. On the Other hand Vertical Axis Wind Turbine (VAWT) can run at low wind speed, independent of wind direction and can be installed anywhere with cheapest cost. The main objective of this research is to improve the design and performance of VAWT to make it more attractive, efficient, durable and sustainable. For a VAWT, the blades perform the main role to extract energy from the wind. Airfoil is considered as the blade for this new design of VAWT. Airfoil has some good aerodynamic characteristics, matches with the characteristics of Savonious type VAWT, such as good stall characteristics and little roughness affect, relatively high drag and low lift coefficient. Three dimensional CAD models of various simple airfoils have been designed in Solidworks. Using these airfoils CFD simulation has been performed for five different VAWT designed models. Moving mesh and fluid flow simulation have been performed using CFD software FLUENT. The findings of these numerical simulations provided pressure contour, velocity contour, drag coefficient, lift coefficient, torque coefficient and power coefficient for all these models. From the results it can be concluded that NACA7510 airfoil VAWT model gives the better performance at higher Tip Speed Ratio (λ) than other models.

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.

Effect of trailing edge dual synthesis jets actuator on aerodynamic characteristics of a straight-bladed vertical axis wind turbine

Energy ◽  
2022 ◽  
Vol 238 ◽  
pp. 121792
Author(s):  
Peilin Wang ◽  
Qingsong Liu ◽  
Chun Li ◽  
Weipao Miao ◽  
Shuai Luo ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Vertical Axis Wind Turbine ◽  
Trailing Edge

scholarly journals CFD for Helical Type Vertical Axis Wind Turbine

2019 ◽  
Vol 9 (2S4) ◽  
pp. 474-476
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Computer Aided Design ◽  
Flow Characteristics ◽  
Vertical Axis ◽  
Urban Environments ◽  
Vertical Axis Wind Turbine ◽  
Wind Turbine System ◽  
Twisted Blade ◽  
Aided Design

Vertical axis wind turbines are most effective for home energy generation especially in urban environments. Wind energy creates a stand-alone energy source that is relied on any place. The main criteria for this work is the design of micro wind turbines for all kinds of applications. Design of Twisted Blade Micro-Wind Turbine system is accomplished using computer aided design with Computational Fluid Dynamics (CFD). The flow characteristics in the wind turbine blade were analyzed by varying its twist ratio. The wind turbines with vertical axis utilize the wind from any direction with no yaw mechanism. The risk of blade ejection besides catching wind from all the directions is avoided by using the helical tye vertical axis wind turbine.

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.

Computational Analysis of Airfoil Merging and its Effect on Performance of Lift Based Vertical Axis Wind Turbine

2016 ◽  
Author(s):  
Akshay Basavaraj
Keyword(s):  
Reynolds Number ◽  
Wind Turbine ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Aerodynamic Characteristics ◽  
Vertical Axis Wind Turbine ◽  
Low Wind Speed ◽  
Naca 0012 ◽  
Selection Of

In regions of low wind speed, overcoming the starting torque of a Vertical Axis Wind Turbine (VAWT) becomes a challenge aspect. In order to overcome this adversity, careful selection of airfoils for the turbine blades becomes a priority. This paper tries to address the issue utilizing an approach wherein by observing the effect of merging two airfoils. Two airfoils which are of varying camber and thickness are merged and their aerodynamic characteristics are evaluated using the software XFOIL 6.96. For a variation in angle of attack from 0 to 90°, aerodynamic analysis is done in order to observe the behavior of one quarter of the entire VAWT cycle. An objective function is developed so as to observe the maximum possible torque generated by these airfoils at Reynolds number varying from 15,000–120,000. Due to change in the value of CL observed at Low Reynolds Number using commercial CFD softwares, multiple objective functions are utilized to observe the behavior over a range of Reynolds number. An experimental co-relation between the cut-in velocity and the lift-coefficient of the airfoils is developed in order to predict the cut-in velocity of the interpolated airfoils. The airfoils used for this paper are NACA 0012, NACA 0018, FX 66 S196, Clark Y (smooth), PT 40, SD 7032, A 18, SD 7080, SG 6043 and SG 6040.

scholarly journals A Dynamic Rotor Vertical-Axis Wind Turbine with a Blade Transitioning Capability

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1446 ◽  
Author(s):  
Elie Antar ◽  
Amne El Cheikh ◽  
Michel Elkhoury
Keyword(s):  
Wind Turbine ◽  
Average Power ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Optimized Design ◽  
Detached Eddy Simulation ◽  
Vertical Axis Wind Turbine ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation

This work presents an optimized design of a dynamic rotor vertical-axis wind turbine (DR VAWT) which maximizes the operational tip-speed ratio (TSR) range and the average power coefficient (Cp) value while maintaining a low cut-in wind velocity. The DR VAWT is capable of mimicking a Savonius rotor during the start-up phase and transitioning into a Darrieus one with increasing rotor radius at higher TSRs. The design exploits the fact that with increasing rotor radius, the TSR value increases, where the peak power coefficient is attained. A 2.5D improved delayed detached eddy simulation (IDDES) approach was adopted in order to optimize the dynamic rotor design, where results showed that the generated blades’ trajectories can be readily replicated by simple mechanisms in reality. A thorough sensitivity analysis was conducted on the generated optimized blades’ trajectories, where results showed that they were insensitive to values of the Reynolds number. The performance of the DR VAWT turbine with its blades following different trajectories was contrasted with the optimized turbine, where the influence of the blade pitch angle was highlighted. Moreover, a cross comparison between the performance of the proposed design and that of the hybrid Savonius–Darrieus one found in the literature was carefully made. Finally, the effect of airfoil thickness on the performance of the optimized DR VAWT was thoroughly analyzed.

Vortex Analytical Model of a Circulation Controlled Vertical Axis Wind Turbine

2009 ◽  
Author(s):  
Jay P. Wilhelm ◽  
Chad C. Panther ◽  
Franz A. Pertl ◽  
James E. Smith
Keyword(s):  
Wind Turbine ◽  
Analytical Model ◽  
Vertical Axis ◽  
Circulation Control ◽  
Vertical Axis Wind Turbine ◽  
Trailing Edge ◽  
Vortex Interactions ◽  
Vortex Model ◽  
Aspect Ratios ◽  
Start Up

A possible method for modeling a Circulation Controlled - Vertical Axis Wind Turbine (CC-VAWT) is a vortex model, based upon the circulation of a turbine blade. A vortex model works by continuously calculating the circulation strength and location of both free and blade vortices which are shed during rotation. The vortices’ circulation strength and location can then be used to compute a velocity at any point in or around the area of the wind turbine. This model can incorporate blade wake interactions, unsteady flow conditions, and finite aspect ratios. Blade vortex interactions can also be studied by this model to assist designers in the avoidance of adverse turbulent operational regions. Conventional vertical axis wind turbine power production is rated to produce power in an operating wind speed envelope. These turbines, unless designed specifically for low speed operation require rotational start-up assistance. The VAWT blade can be augmented to include circulation control capabilities. Circulation control can prolong the trailing edge separation and can be implemented by using blowing slots located adjacent to a rounded trailing edge surface; the rounded surface of the enhanced blade replaces the sharp trailing edge of a conventional airfoil. Blowing slots of the CC-VAWT blade are located on the top and bottom trailing edges and are site-controlled in multiple sections along the span of the blade. Improvements in the amount of power developed at lower speeds and the elimination or reduction of start-up assistance could be possible with a CC-VAWT. In order to design for a wider speed operating range that takes advantage of circulation control, an analytical model of a CC-VAWT would be helpful. The primary function of the model is to calculate the aerodynamic forces experienced by the CC-VAWT blade during various modes of operation, ultimately leading to performance predictions based on power generation. The model will also serve as a flow visualization tool to gain a better understanding of the effects of circulation control on the development and interactions of vortices within the wake region of the CC-VAWT. This paper will describe the development of a vortex analytical model of a CC-VAWT.

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