Numerical Modelling of Savonius Wind Turbine With Downstream Baffle

2015 ◽  
Author(s):  
Ahmed M. El Baz ◽  
Nabil A. Mahmoud ◽  
Ashraf M. Hamed ◽  
Ahmed M. El Kholy
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Dynamics Model ◽  
Small Power ◽  
Turbine Performance ◽  
Savonius Wind Turbine ◽  
Driving Torque

The application of small power wind turbines has been widely spreading over the last decade. The vertical axis wind turbine type is one class which is very attractive in this respect. However, due to its lower performance, it has not been extensively used in such application. The objective of the present paper is to investigate methods of Savonius turbine performance improvement. It is suggested to use a downstream baffle to achieve this goal. The baffle position, length and inclination angle are optimized using 2D Computational Fluid Dynamics model. The model is initially validated by comparison to experimental data reported for the Savonius turbine without baffle. The results show that 40–50% improvement in turbine performance can be obtained by using the optimum baffle design, compared to the turbine performance without baffle. The baffle effect is analyzed and results show that its major role is to reduce the pressure on the backside of the advancing blade. This effect enhances the positive driving torque on the advancing blade of the Savonius turbine and thus increases its power coefficient near the optimum tip speed ratio.

scholarly journals Performance assessment and optimization of a helical Savonius wind turbine by modifying the Bach’s section

2021 ◽  
Vol 3 (8) ◽  
Author(s):  
M. Niyat Zadeh ◽  
M. Pourfallah ◽  
S. Safari Sabet ◽  
M. Gholinia ◽  
S. Mouloodi ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Performance Assessment ◽  
Turbulent Flows ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Tip Speed Ratio ◽  
Basic Model ◽  
Turbine Performance ◽  
Primary Model ◽  
Savonius Wind Turbine

AbstractIn this paper, we attempted to measure the effect of Bach’s section, which presents a high-power coefficient in the standard Savonius model, on the performance of the helical Savonius wind turbine, by observing the parameters affecting turbine performance. Assessment methods based on the tip speed ratio, torque variation, flow field characterizations, and the power coefficient are performed. The present issue was stimulated using the turbulence model SST (k- ω) at 6, 8, and 10 m/s wind flow velocities via COMSOL software. Numerical simulation was validated employing previous articles. Outputs demonstrate that Bach-primary and Bach-developed wind turbine models have less flow separation at the spoke-end than the simple helical Savonius model, ultimately improving wind turbines’ total performance and reducing spoke-dynamic loads. Compared with the basic model, the Bach-developed model shows an 18.3% performance improvement in the maximum power coefficient. Bach’s primary model also offers a 12.4% increase in power production than the initial model’s best performance. Furthermore, the results indicate that changing the geometric parameters of the Bach model at high velocities (in turbulent flows) does not significantly affect improving performance.

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.

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.

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.

Savonius Wind Turbine Performances on Wind Concentrator

2017 ◽  
Vol 8 (1) ◽  
pp. 376
Author(s):  
Dygku. Asmanissa Awg. Osman ◽  
Norzanah Rosmin ◽  
Nor Shahida Hasan ◽  
Baharruddin Ishak ◽  
Aede Hatib Mustaamal@Jamal ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Electrical Power ◽  
Vertical Axis ◽  
Angular Speed ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Air Compressor ◽  
Tip Speed Ratio ◽  
Savonius Wind Turbine ◽  
Air Streams

The air streams from the outlet of an air compressor can be used to generate electricity. For instance, if a micro-sized Vertical-Axis Wind-Turbine (VAWT) is installed towards the airflow, some amount of electricity can be generated before being stored in a battery bank. The research’s objectives are to design, fabricate and analyze the performance of Helical Savonius VAWT blade rotors, which is tested with and without using a wind concentrator. The Helical Savonius VAWT is tested at 0 cm without the concentrator, whereas the blade rotor is tested at concave-blade position when using the concentrator. The blade and the wind concentrator designs were based on the dimensions and the constant airflow of the air compressor. The findings suggested that the blade produced its best performance when tested using wind concentrator at concave-blade position in terms of angular speed (<em>ω</em>), tip speed ratio (<em>TSR</em>) and the generated electrical power (<em>P</em><em><sub>E</sub></em>). The findings concluded that the addition of wind concentrator increases the airflow which then provided better performances on the blades.

scholarly journals PENGARUH JUMLAH BLADE DAN VARIASI PANJANG CHORD TERHADAP PERFORMANSI TURBIN ANGIN SUMBU HORIZONTAL (TASH)

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
I Kade Wiratama ◽  
Made Mara ◽  
L. Edsona Furqan Prina
Keyword(s):  
Wind Turbine ◽  
Energy Use ◽  
Electrical Energy ◽  
Vertical Axis ◽  
Energy System ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine

The willingness of electrical energy is one energy system has a very important role in the economic development of a country's survival. As one energy source (wind) can be converted into electrical energy with the use of a horizontal axis wind turbine. Wind Energy Conversion Systems (WECS) that we know are two wind turbines in general, ie the horizontal axis wind turbine and vertical axis wind turbine is one type of renewable energy use wind as an energy generator. The purpose of this study was to determine the effect of the number of blade and the radius chord of rotation (n), Torque (T), Turbine Power (P), Power Coefficient (CP) and Tip Speed Ratio (λ) generated by the horizontal axis wind turbine with form linear taper. The results show that by at the maximum radius of the chord R3 the number blade 4 is at rotation = 302.700 rpm, Pturbine = 7.765 watt, Torque = 0.245 Nm, λ = 3.168 and Cp = 0.403 or 40.3%.

Performance Improvements for a Vertical Axis Wind Turbine by Means of Gurney Flap

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Yan Yan ◽  
Eldad Avital ◽  
John Williams ◽  
Jiahuan Cui
Keyword(s):  
Wind Turbine ◽  
Stokes Equations ◽  
Numerical Study ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Navier Stokes ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Performance Improvements ◽  
Gurney Flap

Abstract A numerical study was carried out to investigate the effects of a Gurney flap (GF) on the aerodynamics performance of the NACA 00 aerofoil and an associated three-blade rotor of a H-type Darrieus wind turbine. The flow fields around a single aerofoil and the vertical axis wind turbine (VAWT) rotor are studied using unsteady Reynolds-averaged Navier–Stokes equations (URANS). The height of GF ranges from 1% to 5% of the aerofoil chord length. The results show that the GF can increase the lift and lift-to-drag ratio of the aerofoil as associated with the generation of additional vortices near the aerofoil trailing edge. As a result, adding a GF can significantly improve the power coefficient of the VAWT at low tip speed ratio (TSR), where it typically gives low power production. The causing mechanism is discussed in detail, pointing to flow separation and dynamic stall delay.

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>

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°.

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