scholarly journals A COMPARETIVE ANALYSIS OF AERODYNAMIC CHARECTERISTICS OF A VERTICAL AXIS VANE TYPE WIND TURBINE OVER EVEN AND ODD NUMBER OF BLADES

2015 ◽  
Vol 45 (1) ◽  
pp. 14-18
Author(s):  
Zulfa Ferdous ◽  
Md. Quamrul Islam ◽  
M Ali
Keyword(s):  
Reynolds Number ◽  
Dynamic Condition ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Subsonic Wind Tunnel ◽  
Aerodynamic Properties ◽  
Wide Range ◽  
Set Up

This paper reports on the experimental investigation of the aerodynamic effects on even and odd number bladed vertical axis vane type rotor. The experiment was conducted with the help of a subsonic wind tunnel together with the experimental set-up of the vane type rotor and a spring balance. To ensure a Reynolds number independent approach, different stream flow was maintained. The flow velocities varied from 5 m/s to 9 m/s covering the Reynolds number from 0.6375 X 10^5 to 1.2 X 10^5. A four, five and six bladed vertical axis vane typerotor was used to determine the aerodynamic properties in dynamic condition. It is found that the power coefficient increases with increasing the number of blade but the significant effect of even and odd number blade is observed on the range of tip speed ratio. An odd number bladed rotor covered a wide range of tip speed ratio compare to the even number one.

Numerical Research on the Characteristics of Lift-Drag Type Vertical Axis Wind Turbine

2012 ◽  
Vol 189 ◽  
pp. 448-452
Author(s):  
Yan Jun Chen ◽  
Guo Qing Wu ◽  
Yang Cao ◽  
Dian Gui Huang ◽  
Qin Wang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Chord Length ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Middle Range ◽  
Parabolic Form ◽  
Cfd Method

Numerical studies are conducted to research the performance of a kind of lift-drag type vertical axis wind turbine (VAWT) affected by solidity with the CFD method. Moving mesh technique is used to construct the model. The Spalart-Allmaras one equation turbulent model and the implicit coupled algorithm based on pressure are selected to solve the transient equations. In this research, how the tip speed ratio and the solidity of blade affect the power coefficient (Cp) of the small H-VAWT is analyzed. The results indicate that Cp curves exhibit approximate parabolic form with its maximum in the middle range of tip speed ratio. The two-blade wind turbine has the lowest Cp while the three-blade one is more powerful and the four-blade one brings the highest power. With the certain number of blades, there is a best chord length, and too long or too short chord length may reduce the Cp.

Numerical Modeling of Vertical Axis Wind Turbines

2014 ◽  
Author(s):  
Teresa Parra-Santos ◽  
Armando Gallegos-Muñoz ◽  
Miguel A. Rodriguez-Beneite ◽  
Cristobal Uzarraga-Rodriguez ◽  
Francisco Castro-Ruiz
Keyword(s):  
Mechanical Energy ◽  
Vertical Axis ◽  
The Self ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Vertical Axis Wind Turbines ◽  
Selection Of ◽  
Rotor Axis

This paper aims to predict the performance of Vertical Axis Wind Turbine (VAWT), hence the modeling of kinetic energy extraction from wind and its conversion to mechanical energy at the rotor axis, is carried out. The H-type Darrieus turbine consists of three straight blades with shape of aerofoil attached to a rotating vertical shaft. The criterion on the selection of this kind of turbines, despite its reduced efficiency, is the easy manufacture in workshops. A parametric study has been carried out to analyze the camber effect on the non dimensional curves of power coefficient so that the self starting features as well as the range of tip speed ratio of operation could be predicted.

6-DOF Numerical Simulation of the Vertical-Axis Water Turbine

2011 ◽  
Author(s):  
Xin Wang ◽  
Xianwu Luo ◽  
Baotang Zhuang ◽  
Weiping Yu ◽  
Hongyuan Xu
Keyword(s):  
Vertical Axis ◽  
Hydrodynamic Performance ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Test Model ◽  
Tip Speed Ratio ◽  
Water Turbine ◽  
Tidal Stream ◽  
Static Head ◽  
Tidal Stream Turbine

Recent years, the vertical-axis water turbine (VAWT) is widely used for converting the kinetic energy of the moving water in open flow and with low static head like river and tidal sites. Conventional numerical methods such as disk-stream tube method and vortex panel method have some drawbacks to predict the behaviors and characteristics of the vertical-axis tidal stream turbine. This paper had treated the hydrodynamic performance of a VAWT model experimentally and numerically. Based on the present research, a 6-DOF method coupled with CFD suitable to simulate the rotor movement and predict the hydraulic performance for a VAWT was proposed. Compared with the experiments, the numerical results for the performance of the VAWT model were reasonable. It is also noted that there is a maximum power coefficient near tip speed ratio of 2.5 for the test model.

scholarly journals Studi simulasi penggunaan airfoil naca 6412 sebagai sudu pada turbin angin crossflow melalui pemodelan CFD 2 dimensi

2018 ◽  
Vol 13 (1) ◽  
pp. 28
Author(s):  
Muhammad Ivan Fadhil Hendrawan ◽  
Dominicus Danardono ◽  
Syamsul Hadi
Keyword(s):  
Wind Turbine ◽  
Constant Velocity ◽  
Cross Flow ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Ansys Fluent ◽  
Tip Speed Ratio ◽  
Blade Number

AbstractThe simulation aimed to understand the effect of the angle of blade number and blade number of vertical axis wind turbine with cross flow runner to enhance the performance of wind turbine. The turbine had 20, 22, and 24 number of blades. Simulation was done in 2D analysis using ANSYS-Fluent. Tip speed ratio was varied in range of 0,1-0,5 with constant velocity inlet 2 m/s. The effect of blade numbers to torque and power coefficient were analyzed and compared. It had been found that the best power coefficient were 0,5 at tip speed ratio 0,3.

scholarly journals Studi Eksperimen Pengaruh Jumlah Sudu Terhadap Kinerja Wind Turbine Crossflow

2021 ◽  
Vol 16 (2) ◽  
pp. 218
Author(s):  
Fahrudin Fahrudin ◽  
Fitri Wahyuni ◽  
Dini Oktavitasari
Keyword(s):  
Wind Turbine ◽  
Alternative Energy ◽  
Wind Tunnel Test ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Test Scheme ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Torque Coefficient

<p>Wind is an alternative energy that is environmentally friendly and sustainable. Therefore, we need a type of wind turbine that can receive wind from all directions. The crossflow type vertical axis wind turbine has a high torque coefficient at a low tip speed ratio. The purpose of this study was to determine the effect of the number of blades on the performance of the vertical axis crossflow wind turbine. The experimental test was carried out by varying the number of blades. The configuration is analyzed using the experimental wind tunnel test scheme which has been modified in the section test section. The results showed that the number of blades 16 has a power coefficient ( ) = 0.23 tip speed ratio (TSR) = 0.42 at a wind speed of 4 m / s.</p><p><strong><br /></strong></p>

Dynamic Stall: The Case of the Vertical Axis Wind Turbine

1986 ◽  
Vol 108 (2) ◽  
pp. 140-145 ◽  
Author(s):  
A. Laneville ◽  
P. Vittecoq
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Leading Edge ◽  
Vertical Axis ◽  
Dynamic Stall ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Airfoil Surface ◽  
Helicopter Blade ◽  
Tip Speed Ratio

This paper presents the results of an experimental investigation on a driven Darrieus turbine rotating at different tip speed ratios. For a Reynolds number of 3.8 × 104, the results indicate the presence of dynamic stall at tip speed ratio less than 4, and that helicopter blade aerodynamics can be used in order to explain some aspects of the phenomenon. It was observed that in deep stall conditions, a vortex is formed at the leading edge; this vortex moves over the airfoil surface with 1/3 of the airfoil speed and then is shed at the trailing edge. After its shedding, the vortex can interact with the airfoil surface as the blade passes downstream.

scholarly journals Dynamic Stall of a Vertical-Axis Wind Turbine and Its Control Using Plasma Actuation

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3738 ◽  
Author(s):  
Lu Ma ◽  
Xiaodong Wang ◽  
Jian Zhu ◽  
Shun Kang
Keyword(s):  
Wind Turbine ◽  
Tangential Force ◽  
Vertical Axis ◽  
Dynamic Stall ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Dbd Plasma ◽  
Tip Speed Ratio ◽  
Plasma Actuation

In this paper, a dynamic stall control scheme for vertical-axis wind turbine (VAWT) based on pulsed dielectric-barrier-discharge (DBD) plasma actuation is proposed using computational fluid dynamics (CFD). The trend of the wind turbine power coefficient with the tip speed ratio is verified, and the numerical simulation can describe the typical dynamic stall process of the H-type VAWT. The tangential force coefficient and vorticity contours of the blade are compared, and the regular pattern of the VAWT dynamic stall under different tip speed ratios is obtained. Based on the understanding the dynamic stall phenomenon in flow field, the effect of the azimuth of the plasma actuation on the VAWT power is studied. The results show that the azimuth interval of the dynamic stall is approximately 60° or 80° by the different tip speed ratio. The pulsed plasma actuation can suppress dynamic stall. The actuation is optimally applied for the azimuthal position of 60° to 120°.

Vertical Axis Current Turbine (VACT) and its Efficiency

2013 ◽  
Author(s):  
Antonio Carlos Fernandes ◽  
Ali Bakhshandeh Rostami ◽  
Lucas Gomes Canzian ◽  
Sina Mirzaei Sefat
Keyword(s):  
Angular Velocity ◽  
Flat Plate ◽  
Water Channel ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Circulating Water ◽  
Property Changes ◽  
Current Turbine

This study examines the efficiency of a vertical axis current turbine (VACT) according to various non-dimensional mass moments of inertia. The vertical axis current turbine of drag force type with flat plate-shaped blade is tested. From experiments in a circulating water channel the angular velocity, the power coefficient and tip speed ratio of the vertical axis current turbine are obtained. The property changes for various conditions give the relationships between efficiency-related parameters. The maximum power coefficients of experiments occur at the tip speed ratio of approximately 0.35∼0.40. From the experiments, turbine is found to give a 7% power coefficient which related to I* = 0.52.

A Numerical Study on the Effects of Unsteady Wind on Vertical Axis Wind Turbine Performance

2013 ◽  
Author(s):  
Louis Angelo Danao ◽  
Jonathan Edwards ◽  
Okeoghene Eboibi ◽  
Robert Howell
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Numerical Study ◽  
Angle Of Attack ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Peak Performance ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio

Numerical simulations using RANS–based CFD have been utilised to carry out investigations on the effects of unsteady wind in the performance of a wind tunnel vertical axis wind turbine. Using a validated CFD model, unsteady wind simulations revealed a fundamental relationship between instantaneous VAWT CP and wind speed. CFD data shows a CP variation in unsteady wind that cuts across the steady CP curve as wind speed fluctuates. A reference case with mean wind speed of 7m/s, wind speed amplitude of ±12%, fluctuating frequency of 0.5Hz and mean tip speed ratio of 4.4 has shown a wind cycle mean power coefficient of 0.33 that equals the steady wind maximum. Increasing wind speed causes the instantaneous tip speed ratio to fall which leads to higher effective angle of attack and deeper stalling on the blades. Stalled flow and rapid changes in angle of attack of the blade induce hysteresis loops in both lift and drag. Decreasing wind speeds limit the perceived angle of attack seen by the blades to near static stall thus reducing the positive effect of dynamic stall on lift generation. Three mean tip speed ratio cases were tested to study the effects of varying conditions of VAWT operation on the overall performance. As the mean tip speed ratio increases, the peak performance also increases.

scholarly journals Modeling and performance calculation of a horizontal axis wind and hydrokinetic turbine: Numerical study

2018 ◽  
Vol 2 (2) ◽  
pp. 70-79
Author(s):  
Anastas Todorov Yangyozov ◽  
Damjanka Stojanova Dimitrova ◽  
Lazar Georgiev Panayotov
Keyword(s):  
Numerical Study ◽  
Numerical Calculations ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Ansys Cfx ◽  
Hydrokinetic Turbine ◽  
Wide Range ◽  
And Performance ◽  
Performance Calculation

A small turbine, working with air and water to generate electricity, was designed and its performance was reported in this paper. The rotor diameter is 150mm. The numerical calculations of the power coefficient, torque, and tip speed ratio of turbine were carried out for a wide range of inlet velocities. The flow passing through the turbine was investigated with commercial CFD code ANSYS CFX 18

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