An improved LB method for predicting dynamic characteristics of Vertical Axis Wind Turbine airfoils

2022 ◽  
pp. 0309524X2110671
Author(s):  
Shoutu Li ◽  
Qing Wang ◽  
Congxin Yang

One of the important challenges for Vertical Axis Wind Turbine (VAWT) is to fully understand its dynamic characteristics in different operating conditions. Meanwhile, it is necessary to seek a fast and accurate method to evaluate the dynamic characteristic of VAWT. In this study, we improve the LB model by considering the operating principle of VAWT to study the dynamic characteristics of the dedicated and commonly used VAWT airfoils in different operating conditions. The results show that the improved LB model is suitable for simulating the dynamic characteristic of VAWT with a thick airfoil. Although the asymmetric airfoil shows the higher lift coefficient, their dynamic characteristic appears huge fluctuation as the increases of tip speed ratio. Moreover, at a low tip speed ratio, the advantages of the asymmetric airfoil are not obvious. While the dynamic characteristic of the symmetric airfoil is relatively stable with the variation of tip speed ratio.

2015 ◽  
Vol 9 (1) ◽  
pp. 320-323
Author(s):  
Zhang Lijun ◽  
Liu Hua ◽  
Zhang Mingming ◽  
Hu Yi’e

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.


2012 ◽  
Vol 189 ◽  
pp. 448-452
Author(s):  
Yan Jun Chen ◽  
Guo Qing Wu ◽  
Yang Cao ◽  
Dian Gui Huang ◽  
Qin Wang ◽  
...  

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.


Author(s):  
WAHYU AULIA NURWICAKSANA ◽  
BUDHY SETIAWAN ◽  
IKA NOER SYAMSIANA ◽  
SEPTYANA RISKITASARI

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


Author(s):  
Dygku. Asmanissa Awg. Osman ◽  
Norzanah Rosmin ◽  
Nor Shahida Hasan ◽  
Baharruddin Ishak ◽  
Aede Hatib [email protected] ◽  
...  

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.


2020 ◽  
Vol 33 ◽  
pp. 4719-4722
Author(s):  
E. Leelakrishnan ◽  
M. Sunil Kumar ◽  
S. David Selvaraj ◽  
N. Sundara Vignesh ◽  
T.S. Abhesheka Raja

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Vincenzo Dossena ◽  
Giacomo Persico ◽  
Berardo Paradiso ◽  
Lorenzo Battisti ◽  
Sergio Dell'Anna ◽  
...  

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.


2012 ◽  
Vol 229-231 ◽  
pp. 2339-2342
Author(s):  
J.C. Cheng ◽  
S.J Su ◽  
J.J Miau

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.


2021 ◽  
pp. 1-7
Author(s):  
Sobhy Ghoneam ◽  
Ahmed Hamada ◽  
Taha S. Sherif

Abstract This paper presents a comprehensive study of the dynamic behavior of small vertical axis wind turbines (VAWTs) based on local fabricated Savonius VAWTs, which is suitable for countries that have moderate wind speed. The merits of this design are cleanliness, silent, start-up under low wind speed, independent wind directions, adaptability and ease of manufacturing. Also, this paper presents an experimental validation study for the optimized Savonius VAWT. Four verification test configurations of the optimized VAWT composite blades are designed, simulated and fabricated of Glass – Polyester with different stacking sequence layout for each. Modified mechanical parameters are introduced to improve the scalability, reliability, and accuracy of the developed models. Based on wind energy conversion system basics, aerodynamic characteristics (tip speed ratio (λ) and coefficient of power (Cp)), dynamic characteristics (natural frequencies and mode shapes) of Savonius-rotor models are presented and simulated within SOLIDWORKS Simulation 2020 software. The dynamic characteristics such as frequency, mode shape and damping factor are extensively investigated using Fast Fourier Transformer (FFT) analyzer. The results show that the role of composite material blades in improving the dynamic performance of a wind turbine is significant.


2013 ◽  
Vol 2013.62 (0) ◽  
pp. 257-258
Author(s):  
Toshiaki KAWABATA ◽  
Takao MAEDA ◽  
Yasunari KAMADA ◽  
Junsuke MURATA ◽  
Qing'an LI

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