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

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

Volume 6B: Energy ◽

10.1115/imece2013-62493 ◽

2013 ◽

Cited By ~ 1

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.

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Performance Analysis and Optimization of a Vertical-Axis Wind Turbine with a High Tip-Speed Ratio

Energies ◽

10.3390/en14040996 ◽

2021 ◽

Vol 14 (4) ◽

pp. 996

Author(s):

Liang Li ◽

Inderjit Chopra ◽

Weidong Zhu ◽

Meilin Yu

Keyword(s):

Wind Turbine ◽

Pitch Angle ◽

Angle Of Attack ◽

Vertical Axis ◽

Speed Ratio ◽

Vertical Axis Wind Turbine ◽

Aerodynamic Loads ◽

Tip Speed Ratio ◽

Aerodynamic Model ◽

Lift And Drag

In this work, the aerodynamic performance and optimization of a vertical-axis wind turbine with a high tip-speed ratio are theoretically studied on the basis of the two-dimensional airfoil theory. By dividing the rotating plane of the airfoil into the upwind and downwind areas, the relationship among the angle of attack, azimuth, pitch angle, and tip-speed ratio is derived using the quasi-steady aerodynamic model, and aerodynamic loads on the airfoil are then obtained. By applying the polynomial approximation to functions of lift and drag coefficients with the angle of attack for symmetric and asymmetric airfoils, respectively, explicit expressions of aerodynamic loads as functions of the angle of attack are obtained. The performance of a fixed-pitch blade is studied by employing a NACA0012 model, and influences of the tip speed ratio, pitch angle, chord length, rotor radius, incoming wind speed and rotational speed on the performance of the blade are discussed. Furthermore, the optimization problem based on the dynamic-pitch method is investigated by considering the maximum value problem of the instantaneous torque as a function of the pitch angle. Dynamic-pitch laws for symmetric and asymmetric airfoils are derived.

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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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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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