Effect of solidity on the dynamic behaviour of the Darrieus turbine with leading-edge protuberance

Abstract The dynamic behaviour of the straight–type Darrieus turbine with leading-edge protuberance (LEP) was analysed under various solidity ratios at several tip speed ratios through experiments. The Darrieus turbine is a type of Vertical Axis Wind Turbine (VAWT) which uses wind energy to generate electricity. This type of turbine was subjected to vortex-induced and buffeting types of vibrations. These vibrations were more sensitive to the number of blades and tip speed ratios. Based on the experimental measurements, the results revealed that, at a low tip speed ratio, the four-bladed turbine exhibits lesser vortex-induced vibrations than those of the three and five-bladed turbines. However, at a high tip speed ratio, the three-bladed configuration operates well against the vortex-induced vibrations. In the case of buffeting, a three-bladed turbine diminishes the dynamic oscillations at both low and high tip speed ratios, whereas the four and five-bladed turbines induce dynamic oscillations at slightly higher amplitudes. However, the amplitude of buffeting is smaller than those of vortex-induced vibrations.

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Experimental Study of Wind Booster Addition for Savonius Vertical Wind Turbine of Two Blades Variations Using Low Wind Speed

E3S Web of Conferences ◽

10.1051/e3sconf/201912514003 ◽

2019 ◽

Vol 125 ◽

pp. 14003

Author(s):

Eflita Yohana ◽

MSK. Tony Suryo U ◽

Binawan Luhung ◽

Mohamad Julian Reza ◽

M Badruz Zaman

Keyword(s):

Wind Speed ◽

Wind Energy ◽

Wind Turbine ◽

Vertical Axis ◽

Vertical Wind ◽

Speed Ratio ◽

Vertical Axis Wind Turbine ◽

Tip Speed Ratio ◽

Average Value ◽

Low Wind Speed

The Wind turbine is a tool used in Wind Energy Conversion System (WECS). The wind turbine produces electricity by converting wind energy into kinetic energy and spinning to produce electricity. Vertical Axis Wind Turbine (VAWT) is designed to produce electricity from winds at low speeds. Vertical wind turbines have 2 types, they are wind turbine Savonius and Darrieus. This research is to know the effect of addition wind booster to Savonius vertical wind turbine with the variation 2 blades and 3 blades. Calculation the power generated by wind turbine using energy analysis method using the concept of the first law of thermodynamics. The result obtained is the highest value of blade power in Savonius wind turbine without wind booster (16.5 ± 1.9) W at wind speed 7 m/s with a tip speed ratio of 1.00 ± 0.01. While wind turbine Savonius with wind booster has the highest power (26.3 ± 1.6) W when the wind speed of 7 m/s with a tip speed ratio of 1.26 ± 0.01. The average value of vertical wind turbine power increases Savonius after wind booster use of 56%.

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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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Design and performance evaluation of vertical axis wind turbine for wind energy harvesting at railway

World Journal of Science Technology and Sustainable Development ◽

10.1108/wjstsd-11-2020-0088 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Hashwini Lalchand Thadani ◽

Fadia Dyni Zaaba ◽

Muhammad Raimi Mohammad Shahrizal ◽

Arjun Singh Jaj A. Jaspal Singh Jaj ◽

Yun Ii Go

Keyword(s):

Wind Speed ◽

Energy Harvesting ◽

Wind Energy ◽

Wind Turbine ◽

High Speed ◽

Vertical Axis ◽

Speed Ratio ◽

Vertical Axis Wind Turbine ◽

Modeling Tools ◽

Content Type

PurposeThis paper aims to design an optimum vertical axis wind turbine (VAWT) and assess its techno-economic performance for wind energy harvesting at high-speed railway in Malaysia.Design/methodology/approachThis project adopted AutoCAD and ANSYS modeling tools to design and optimize the blade of the turbine. The site selected has a railway of 30 km with six stops. The vertical turbines are placed 1 m apart from each other considering the optimum tip speed ratio. The power produced and net present value had been analyzed to evaluate its techno-economic viability.FindingsComputational fluid dynamics (CFD) analysis of National Advisory Committee for Aeronautics (NACA) 0020 blade has been carried out. For a turbine with wind speed of 50 m/s and swept area of 8 m2, the power generated is 245 kW. For eight trains that operate for 19 h/day with an interval of 30 min in nonpeak hours and 15 min in peak hours, total energy generated is 66 MWh/day. The average cost saved by the train stations is RM 16.7 mil/year with battery charging capacity of 12 h/day.Originality/valueWind energy harvesting is not commonly used in Malaysia due to its low wind speed ranging from 1.5 to 4.5 m/s. Conventional wind turbine requires a minimum cut-in wind speed of 11 m/s to overcome the inertia and starts generating power. Hence, this paper proposes an optimum design of VAWT to harvest an unconventional untapped wind sources from railway. The research finding complements the alternate energy harvesting technologies which can serve as reference for countries which experienced similar geographic constraints.

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Kontrol Angle of Attack untuk Optimasi Daya padaVertical Axis Wind Turbine Tipe Darrieus

ELKOMIKA Jurnal Teknik Energi Elektrik Teknik Telekomunikasi & Teknik Elektronika ◽

10.26760/elkomika.v8i3.492 ◽

2020 ◽

Vol 8 (3) ◽

pp. 492

Author(s):

WAHYU AULIA NURWICAKSANA ◽

BUDHY SETIAWAN ◽

IKA NOER SYAMSIANA ◽

SEPTYANA RISKITASARI

Keyword(s):

Wind Turbine ◽

Angle Of Attack ◽

Vertical Axis ◽

Speed Ratio ◽

Trial And Error ◽

Proportional Integral Derivative ◽

Vertical Axis Wind Turbine ◽

Average Efficiency ◽

Proportional Integral ◽

Tip Speed Ratio

ABSTRAKVAWT (Vertical Axis Wind Turbine) tipe Darrieus NACA0015 merupakan salah satu model dari turbin angin yang bekerja dengan menggunakan angin sebagai sumber penggerak. Namun dari hasil pengamatan, kecepatan angin yang ada tidak konstan setiap saat. Sehingga dari permasalahan ini perlu suatu kontrol yaitu dengan mengendalikan sudut kerja blade VAWT yang dikenal dengan kontrol angle of attack (AoA). Prinsip kerja kontrol AoA yaitu sudut blade diatur agar VAWT bekerja secara optimum dan dapat meningkatkan efisiensi. Metode kontrol AoA menggunakan PID (Proportional–Integral–Derivative) dengan memberikan nilai trial and error pada Kp, Ki, Kd. VAWT ini menggunakan konstanta TSR (Tip Speed Ratio) yaitu 4. Hasil dari penelitian ini yaitu daya yang dihasilkan VAWT dengan kontrol AoA mendapatkan rata-rata efisiensi sebesar 5.16%, sedangkan VAWT tanpa kontrol mendapatkan efisiensi sebesar 3.49%. Sehingga dapat disimpulkan bahwa dengan kontrol AoA, rata-rata efisiensi dayanya naik sebesar 1.67% dari yang tanpa kontrol.Kata Kunci: Kontrol Angle of Attack (AoA), VAWT, TSR, Efisiensi ABSTRACTVAWT (Vertical Axis Wind Turbine) type Darrieus NACA0015 is one model of a wind turbine that works by using wind as a source of propulsion. Conditions from observations, wind speeds that are not constant every time. So from this problem needs control VAWT by controlling the working angle of the VAWT blade is the angle of attack control (AoA). The principle AoA control is that the blade angle adjusted so that the VAWT works optimally and can improve the efficiency. AoA control method uses PID (Proportional-Integral-Derivative) by providing trial and error values for Kp, Ki, Kd. VAWT uses TSR (Tip Speed Ratio) constant which is 4. The results of this research, VAWT with AoA control get an average efficiency of 5.16%, while without control gets an average efficiency of 3.49%. So it can be concluded that with AoA control, the average power efficiency increases by 1.67% from those without control.Keywords: Angle of Attack (AoA) Control, VAWT, TSR, Efficiency

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Savonius Wind Turbine Performances on Wind Concentrator

International Journal of Power Electronics and Drive Systems (IJPEDS) ◽

10.11591/ijpeds.v8.i1.pp376-383 ◽

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 (ω), tip speed ratio (TSR) and the generated electrical power (PE). The findings concluded that the addition of wind concentrator increases the airflow which then provided better performances on the blades.

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Numerical evaluation of optimum tip speed ratio for darrieus type vertical axis wind turbine

Materials Today Proceedings ◽

10.1016/j.matpr.2020.08.352 ◽

2020 ◽

Vol 33 ◽

pp. 4719-4722

Author(s):

E. Leelakrishnan ◽

M. Sunil Kumar ◽

S. David Selvaraj ◽

N. Sundara Vignesh ◽

T.S. Abhesheka Raja

Keyword(s):

Wind Turbine ◽

Numerical Evaluation ◽

Vertical Axis ◽

Speed Ratio ◽

Vertical Axis Wind Turbine ◽

Tip Speed Ratio

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An Experimental Study of the Aerodynamics and Performance of a Vertical Axis Wind Turbine in a Confined and Unconfined Environment

Journal of Energy Resources Technology ◽

10.1115/1.4030448 ◽

2015 ◽

Vol 137 (5) ◽

Cited By ~ 45

Author(s):

Vincenzo Dossena ◽

Giacomo Persico ◽

Berardo Paradiso ◽

Lorenzo Battisti ◽

Sergio Dell'Anna ◽

...

Keyword(s):

Experimental Study ◽

Wind Tunnel ◽

Wind Turbine ◽

Vertical Axis ◽

Tip Vortex ◽

Speed Ratio ◽

Vertical Axis Wind Turbine ◽

Tip Speed Ratio ◽

And Performance ◽

Power Curves

This paper presents the results of a wide experimental study on an H-type vertical axis wind turbine (VAWT) carried out at the Politecnico di Milano. The experiments were carried out in a large-scale wind tunnel, where wind turbines for microgeneration can be tested in real-scale conditions. Integral torque and thrust measurements were performed, as well as detailed aerodynamic measurements to characterize the flow field generated by the turbine downstream of the rotor. The machine was tested in both a confined (closed chamber) and unconfined (open chamber) environment, to highlight the effect of wind tunnel blockage on the aerodynamics and performance of the VAWT under investigation. The experimental results, compared with the blockage correlations presently available, suggest that specific correction models should be developed for VAWTs. The experimental thrust and power curves of the turbine, derived from integral measurements, exhibit the expected trends with a peak power coefficient of about 0.28 at tip-speed ratio equal to 2.5. Flow measurements, performed in three conditions for tip speed ratio equal to 1.5, 2.5, and 3.5, show the fully three-dimensional character of the wake, especially in the tip region where a nonsymmetrical wake and tip vortex are found. The unsteady evolution of the velocity and turbulence fields further highlights the effect of aerodynamic loading on the wake unsteadiness, showing the time-dependent nature of the tip vortex and the onset of dynamic stall for tip speed ratio lower than 2.

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Application of Variable Blade Pitch Control on Improving the Performance of Vertical Axis Wind Turbine

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.229-231.2339 ◽

2012 ◽

Vol 229-231 ◽

pp. 2339-2342

Author(s):

J.C. Cheng ◽

S.J Su ◽

J.J Miau

Keyword(s):

Wind Turbine ◽

Vertical Axis ◽

Aerodynamic Characteristics ◽

Speed Ratio ◽

Vertical Axis Wind Turbine ◽

Energy Capture ◽

Pitch Control ◽

Tip Speed Ratio ◽

Torque Coefficient ◽

Variable Pitch Control

A three blades vertical axis wind turbine simulation is performed to study the unsteady aerodynamic characteristics with blade pitch control. Several fixed and variable blade pitch models under different tip speed ratio are adopted to improve performance of the wind turbine. Results show that an appropriate pitch control model can effectively decrease the range of negative torque regime to reduce the vibration of the wind turbine. Besides, the average torque coefficient as well as the energy capture efficiency can be also improved, especially for the lower tip speed ratio. The overall efficiency of the wind turbines in power generation will be enhanced. For the cases under the tip speed ratio between 1 and 3, the efficiency can be enhanced 243% and 486% for fixed and variable pitch control models respectively as comparing with non-pitch control cases.

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Determination Method of Critical Best Tip Speed Ratio for the Vertical Axis Wind Turbine

The Open Mechanical Engineering Journal ◽

10.2174/1874155x01509010320 ◽

2015 ◽

Vol 9 (1) ◽

pp. 320-323

Author(s):

Zhang Lijun ◽

Liu Hua ◽

Zhang Mingming ◽

Hu Yi’e

Keyword(s):

Wind Turbine ◽

Lift Coefficient ◽

Tangential Force ◽

Angle Of Attack ◽

Vertical Axis ◽

Position Angle ◽

Speed Ratio ◽

Vertical Axis Wind Turbine ◽

Tip Speed Ratio ◽

The Relationship

Tip speed ratio is an important parameter of describing wind turbine performance. Based on vane airfoil profile, the relationship between vane lift coefficient, drag coefficient and angle of attack is calculated by means of Profili software. The corresponding stall angle is also obtained. The relationship between the position angle of vane and angle of attack at different tip speed ratios is drawn by Matlab software and the corresponding best tip speed ratio is determined rapidly. Based on it, the airfoil tangential force is also analyzed for different vane airfoil profiles in the condition of same Reynolds number.

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