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

2015 ◽  
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 ◽  
And Performance ◽  
Confined Environment ◽  
Power Curves

This paper presents the results of a wide experimental study on an H-type Vertical Axis Wind Turbine (VAWT) carried out at Politecnico di Milano in the frame of the national founded project PRIN 2009. The experiments were carried out in the large-scale wind tunnel of the Politecnico di Milano, where real-scale wind turbines for micro generation can be tested in full similarity 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 confined and non-confined 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 λ = 2.5. Detailed flow measurements, performed in three conditions for λ 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 non-symmetrical wake and tip vortex are found. The unsteady evolution of the velocity and turbulence fields further highlight the effect of aerodynamic loading on the wake unsteadiness, showing the time-dependent nature of the tip vortex and the onset of a non-symmetric dynamic stall for λ lower than 2.

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

2015 ◽  
Vol 137 (5) ◽  
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.

scholarly journals Experimental Study of Vertical Axis Wind Turbine Performance under Vibration

2021 ◽  
Vol 1 (2) ◽  
pp. 177-185
Author(s):  
Md Rasel Sarkar ◽  
Sabariah Julai ◽  
Mst Jesmin Nahar ◽  
Moslem Uddin ◽  
Mahmudur Rahman ◽  
...  
Keyword(s):  
Power Generation ◽  
Experimental Study ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Dynamic Characteristics ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Flow Uniformity ◽  
Aerodynamic Forces ◽  
Turbine Performance

An experimental study was conducted to study the effects of flow uniformity on vibration and power generation of a small vertical axis wind turbine (VAWT). Previous studies have confirmed that one of the sources of vibration in the turbine is due to aerodynamic forces, which are due to incident wind. Firstly, understanding vibration is essential before proceeding to the measurements. In this experiment, further understand the vibrations of the turbine in operation, the operating deflection shape (ODS) technique was used. A wind tunnel and flow conditioner were fabricated. Experimental modal analysis (EMA) was conducted, and the dynamic characteristics are gathered. The ODS was conducted for operating the turbine at different speeds, with and without the flow conditioner. Results from EMA and ODS are correlated to explain the behavior of structures. In conclusion, the flow conditioner tested did have a big impact on the response of the structure in terms of vibration up to 30% indifference, but not so much in power generated about 2% indifference.

scholarly journals NUMERICAL AND EXPERIMENTAL STUDY OF A TWO-STAGE SAVONIUS WIND TURBINE

2019 ◽  
Vol 18 (2) ◽  
pp. 52
Author(s):  
L. B. Kothe ◽  
A. P. Petry
Keyword(s):  
Experimental Study ◽  
Numerical Simulations ◽  
Wind Turbine ◽  
Vertical Axis ◽  
Relative Difference ◽  
Performance Comparison ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Two Stage ◽  
Index Method

This article presents a numerical and experimental study of vertical axis wind turbine performance comparison involving a two-stage Savonius rotor with similar parameters. The experimental study is conducted in the aerodynamic tunnel at the Fluid Mechanics Laboratory of the Federal University of Rio Grande do Sul. The aerodynamics rotors are manufactured by 3D prototyping technique. Numerical simulations are performed using the Finite Volumes Method performed by the solution of the Reynolds Averaged Navier-Stokes (RANS) and continuity equations using the SST k-ω turbulence model. The numerical domain is modeled in order to maintain the same characteristics of the experimental model. The mesh quality is evaluated through the GCI (Grid Convergence Index) method. The static and dynamic torque coefficients and the power coefficients are compared. The tests are made without blockage corrections due to the small blockage ratio from 7.5%. Results show that the turbine has a positive static torque coefficient for any rotor angles. The dynamic torque reaches the maximum value for a tip speed ratio (λ) of 0.2 for the experimental and numerical cases. The relative difference between the numerical simulations and the experimental results are between 3.8% and 13.4%.

A Straight-Bladed Vertical Axis Wind Turbine With a Directed Guide Vane Row

2007 ◽  
Author(s):  
Manabu Takao ◽  
Takao Maeda ◽  
Yasunari Kamada ◽  
Michiaki Oki ◽  
Hideki Kuma
Keyword(s):  
Experimental Study ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Aerodynamic Force ◽  
Guide Vane ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Vertical Axis Turbine

A straight-bladed vertical axis wind turbine with a directed guide vane row has been proposed in order to enhance its torque. The experimental study of the proposed wind turbine was carried out by a wind tunnel with an outlet diameter of 1.8m. The tested rotor has some straight rotor blades with a profile of NACA0015, a radius diameter of 0.3 m and a height of 0.7 m. The guide vane row having 3 arc plates rotates around the rotor and is directed to the wind by aerodynamic force generated by tail vanes, so as to put the guide vane row in upstream of the rotor. As a result, the performance of the straight-bladed vertical axis turbine was improved by means of the directed guide vane row. Further, by the use of the guide vane row adopted in the study, the power coefficient of the proposed wind turbine was approximately 1.5 times higher than that of the original wind turbine which has no guide vane.

scholarly journals Design, Fabrication, and Performance Test of a 100-W Helical-Blade Vertical-Axis Wind Turbine at Low Tip-Speed Ratio

Energies ◽  
2018 ◽  
Vol 11 (6) ◽  
pp. 1517 ◽  
Author(s):  
Dowon Han ◽  
Young Heo ◽  
Nak Choi ◽  
Sang Nam ◽  
Kyoung Choi ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Performance Test ◽  
Vertical Axis ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbine ◽  
Tip Speed Ratio ◽  
Helical Blade ◽  
And Performance

Rotor Design and Performance Study of a Vertical-Axis Wind Turbine Based on DMS

2013 ◽  
Vol 448-453 ◽  
pp. 1892-1896
Author(s):  
Rui Yang ◽  
Jin Long Li ◽  
Wei Wei Xia ◽  
Ting Ting Wang
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Aerodynamic Load ◽  
Vertical Axis Wind Turbine ◽  
Performance Study ◽  
Force Coefficient ◽  
Rotor Design ◽  
And Performance

Specifically address the design of a 5KW H-type vertical-axis wind turbine (H-VAWT) with NACA 0018 airfoil considering the factors that affect wind turbine power. The double-multiple streamtube (DMS) theoretical model is analyzed and summarized and calculated by Matlab. The 5KW H-type vertical axis wind turbines aerodynamic performance is calculated by the model written in Matlab. The curve of the power coefficient as a function of the tip-speed ratio and the curve of the normal force coefficient and the tangential farce as a function of the blade position is given by Matlab. From the curves we can see that upwind rotor aerodynamic load is larger, downwind rotor aerodynamic load is smaller and there is a serious flow retarding effect in the rotor downwind area.

Experimental Study of a Straight-Bladed Vertical Axis Wind Turbine With a Directed Guide Vane Row

2009 ◽  
Author(s):  
Manabu Takao ◽  
Hiroyuki Takita ◽  
Yohei Saito ◽  
Takao Maeda ◽  
Yasunari Kamada ◽  
...  
Keyword(s):  
Experimental Study ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Velocity ◽  
Guide Vane ◽  
Vertical Axis ◽  
Chord Length ◽  
Vertical Axis Wind Turbine ◽  
Guide Vanes ◽  
Blade Height

The objective of this study is to show the effect of guide vane geometry on the performance of wind turbine. In order to overcome the disadvantages of vertical axis wind turbine, a straight-bladed vertical axis wind turbine (S-VAWT) with a directed guide vane row has been proposed and tested by the authors. According to previous studies, it was clarified that the performance of the turbine can be improved by means of the directed guide vane row. However, the guide vane geometry of S-VAWT has not been optimized so far. In order to clarify the effect of guide vane geometry, the effects of distance between the guide vanes and the number of guide vanes on power and torque coefficients were investigated in the experiments. The experimental study was carried out by a wind tunnel. The wind tunnel with a diameter of 1.8m is open jet type. The wind velocity is from 5 to 9 m/s in the experiments. The rotor has three straight blades with a profile of NACA4518 and a chord length of 100 mm, a diameter of 0.6 m and a blade height of 0.7 m. The guide vane row consists of some arc plates.

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.

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