Performance and Flow Condition of Cross-Flow Wind Turbine With a Symmetrical Casing

A cross-flow wind turbine has a high torque coefficient at a low tip speed ratio. Therefore, it is a good candidate for use as a self-starting turbine. Furthermore, it has low noise and excellent stability; therefore, it has attracted attention from the viewpoint of applications as a small wind turbine for an urban district. However, its maximum power coefficient is extremely low (10%) as compared to that of other small wind turbines. Prevailing winds in two directions often blow in urban and coastal regions. Therefore, in order to improve the performance and the flow condition of the cross-flow rotor, a casing suitable for this sort of prevailing wind conditions is designed in this research and the effect of the casing is investigated by experimental and numerical analysis. In the experiment, a wind tunnel with a square discharge is used and main flow velocity is set as 20 m/s. A torque meter, a rotational speed pickup, and a motor are assembled with the same axis as the test wind turbine and the tip speed ratio is changeable by a rotational speed controller. The casing is set around the cross-flow rotor and flow distribution at the rotor inlet and the outlet is measured by a one-hole pitot tube. The maximum power coefficient is obtained as Cpmax = 0.19 with the casing, however Cpmax = 0.098 without the casing. It is clear that the inlet and the outlet flow condition is improved by the casing. In the present paper, in order to improve the performance of a cross-flow wind turbine, a symmetrical casing suitable for prevailing winds in two directions is proposed. Then, the performance and the internal flow condition of the cross-flow wind turbine with the casing are clarified. Furthermore, the influence of the symmetrical casing on performance is discussed and the relation between the flow condition and performance is considered.

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Study on Performance and Flow Condition of Cross-Flow Wind Turbine With a Symmetrical Casing

Volume 1: Symposia, Parts A, B and C ◽

10.1115/fedsm2009-78311 ◽

2009 ◽

Author(s):

Junichiro Fukutomi ◽

Toru Shigemitsu ◽

Hiroki Daito

Keyword(s):

Wind Turbine ◽

Rotational Speed ◽

Flow Condition ◽

Cross Flow ◽

Low Noise ◽

Maximum Power ◽

Power Coefficient ◽

Urban Region ◽

Prevailing Wind ◽

The Cross

Wind turbine has been attracted as the technology for clean and renewable energy and many kinds of the researches and the developments are performed. Cross-flow wind turbine has a characteristic of good self-starting, low noise and high stability. Therefore, it is expected as the small-sized wind turbine for urban district. But the maximum power coefficient of the cross-flow wind turbine is extremely low as 10%. Wind in an urban region and a coastal place has a prevailing wind of two directions to occur in a specific condition frequently. Then, a casing suitable for this prevailing wind was designed in this research and the effect of the casing was investigated by experimental and numerical analysis. In the experiment, a wind tunnel with a square discharge 500mm×500mm was used and main flow velocity was set as 20m/s to reduce the influence of measurement error on performance. A torque meter, a rotational speed pickup and a motor were assembled with the same axis at low position of a test wind turbine which was set vertically and rotational speed and tip speed ratio were changeable by a rotational speed controller. The casing was set around the cross-flow rotor and flow distribution at the rotor inlet and the outlet was measured by a one-hole pitot tube. The maximum power coefficient was obtained as Cpmax = 0.19 with the casing, however as Cpmax = 0.098 without the casing. And it was clarified that the inlet and the outlet flow condition was improved by the casing. In the present paper, in order to improve the performance of a cross-flow wind turbine, a symmetrical casing suitable for the prevailing wind of two directions is proposed. Then performance and internal flow condition of the cross-flow wind turbine with the casing is clarified. Furthermore, the influence of a symmetrical casing on performance is discussed and the relation between flow condition and performance is considered.

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Study on Performance and Internal Flow of Cross-Flow Wind Turbine

Volume 2: Symposia, Parts A, B, and C ◽

10.1115/fedsm2003-45101 ◽

2003 ◽

Author(s):

Kazuki Takeuchi ◽

Junichiro Fukutomi ◽

Hidetoshi Kodani ◽

Hironori Horiguchi

Keyword(s):

Wind Turbine ◽

Pressure Difference ◽

Main Part ◽

Cross Flow ◽

Internal Flow ◽

Power Coefficient ◽

Construction Costs ◽

Outer Flow ◽

Output Coefficient ◽

The Cross

The wind turbine has become more popular in recent years, but on the other hand, the developments of small wind-turbine have been legging behind. Because, the energy density of wind is small, since the efficiency of the main part of a wind turbine is very low. The construction costs become comparatively high-priced. Then, the main part of this subject is to show that, by collecting and sucking out more winds, a wind turbine is made to pass many winds and the new cross-flow wind turbine that increases an output coefficient is proposed. The cross-flow wind turbine has high torque and low speed characteristics and the structure are very simple. So, it can be used in a large wind velocity region. However, even if the power coefficient is high, it is about 10%. The purpose of this paper is to show how we can improve the power coefficient by applying a casing, which has a nozzle and a diffuser. This research was made to clear up fundamental characteristics of the interaction between outer flow and inner flow. Three kinds of cross-flow wind turbines were designed. The nozzle and diffuser have been designed suitable for the performance of wind turbine. The flow simulations by CFD have been carried out for various types of casings at 20 m/s with Fluent Ver5.0. All Wind tunnel experiments were performed at 20m/s. The case of casing 2, which have plate arranged near the separation point of cylinder, also experimented. The rotor that is settled in the casing 1 shows a larger power coefficient than the case without a casing. The casing of the cross-flow turbine makes a pressure difference between inflow and outflow. The pressure difference increases the mass flow rate. Therefore much more wind passes through into the cross-flow turbine. In this experiment, the power coefficient increased 1.5 times in the case with casing. A still higher output coefficient could be obtained in the case where it is shown by the casing 2.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.215-216.1323 ◽

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.

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

Jurnal Teknik Mesin Indonesia ◽

10.36289/jtmi.v13i1.87 ◽

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.

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Performance Prediction and Validation of a Small-Capacity Twisted Savonius Wind Turbine

Energies ◽

10.3390/en12091721 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1721 ◽

Cited By ~ 3

Author(s):

Hyeonmu Jang ◽

Insu Paek ◽

Seungjoo Kim ◽

Deockjin Jeong

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Wind Turbine ◽

Performance Test ◽

Cfd Simulation ◽

Power Production ◽

Maximum Power ◽

Power Coefficient ◽

Speed Ratio ◽

Simulation Results

In this study, an off-grid–type small wind turbine for street lighting was designed and analyzed. Its performance was predicted using a computational fluid dynamics model. The proposed wind turbine has two blades with a radius of 0.29 m and a height of 1.30 m. Ansys Fluent, a commercial computational fluid dynamics solver, was used to predict the performance, and the k-omega SST model was used as the turbulence model. The simulation result revealed a tip-speed ratio of 0.54 with a maximum power coefficient, or an aerodynamic rotor efficiency of 0.17. A wind turbine was installed at a measurement site to validate the simulation, and a performance test was used to measure the power production. To compare the simulation results obtained from the CFD simulation with the measured electrical power performance, the efficiencies of the generator and the controller were measured using a motor-generator testbed. Also, the control strategy of the controller was found from the field test and applied to the simulation results. Comparing the results of the numerical simulation with the experiment, the maximum power-production error at the same wind speed was found to be 4.32%.

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

SN Applied Sciences ◽

10.1007/s42452-021-04731-0 ◽

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.

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Attenuation of Cross-Flow Fan Noise Using Porous Stabilizers

International Journal of Rotating Machinery ◽

10.1155/2011/528927 ◽

2011 ◽

Vol 2011 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Huanxin Lai ◽

Meng Wang ◽

Chuye Yun ◽

Jin Yao

Keyword(s):

Cross Flow ◽

Sound Radiation ◽

Internal Flow ◽

Considerable Effect ◽

Front Wall ◽

Performance Curve ◽

Fan Noise ◽

Aerodynamic Performances ◽

The Cross ◽

Cross Flow Fan

This paper presents a qualitative analysis of controlling the cross-flow fan noise by using porous stabilizers. The stabilizer was originally a folded plate. It is changed into a porous structure which has a plenum chamber and vent holes on the front wall. In order to investigate the influences of using the porous stabilizers, experiments are carried out to measure the cross-flow fan aerodynamic performances and sound radiation. Meanwhile, the internal flow field of the fan is numerically simulated. The results show that the porous stabilizers have not produced considerable effect on the cross-flow fan's performance curve, but the noise radiated from the fan is strongly affected. This indicates the feasibility of controlling the cross-flow fan noise by using the porous stabilizers with selected porosity.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.189.448 ◽

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.

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Performance study of twisted Darrieus hydrokinetic turbine with novel blade design

Journal of Energy Resources Technology ◽

10.1115/1.4051483 ◽

2021 ◽

pp. 1-37

Author(s):

Mabrouk Mosbahi ◽

Mouna Derbel ◽

Mariem Lajnef ◽

Bouzid Mosbahi ◽

Zied Driss ◽

...

Keyword(s):

Three Dimensional ◽

Maximum Power ◽

Power Coefficient ◽

Speed Ratio ◽

Small Scale ◽

Performance Study ◽

Hydrokinetic Turbine ◽

Blade Shape ◽

Water Turbine ◽

Water Canals

Abstract Twisted Darrieus water turbine is receiving growing attentiveness for small-scale hydropower generation. Accordingly, the need for raised water energy conversion incentivizes researchers to focalise on the blade shape optimization of twisted Darrieus turbine. In view of this, an experimental analysis has been performed to appraise the efficiency of a spiral Darrieus water rotor in the present work. To better the performance parameters of the studied water rotor with twisted blades, three novel blade shapes, namely U-shaped blade, V-shaped blade and W-shaped blade, have been numerically tested using a computational fluid dynamics three-dimensional numerical model. Maximum power coefficient of Darrieus rotor reaches 0.17 at 0.63 tip-speed ratio using twisted blades. Using V-shaped blades, maximum power coefficient has been risen up to 0.185. The current study could be practically applied to provide more effective employment of twisted Darrieus turbines and to improve the generated power from flowing water such as river streams, tidal currents, or other man made water canals.

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