Design For Accessibility: Getting it right from the start
Numerical analysis of Vertical Axis Wind Turbine
1. Numerical Analysis of Vertical Axis Wind
Turbine
Mohammad Rashedul Hasan, Md. Rasedul Islam,
G.M Hasan Shahariar and Dr. Mohammad Mashud
Department of Mechanical Engineering
Khulna University of Engineering & Technology, Khulna, Bangladesh
IFOST-2014, Bangladesh
3. INTRODUCTION
A wind turbine is a rotating device which converts kinetic energy of wind
into electrical energy
Horizontal Axis Wind Turbine Vertical Axis Wind Turbine
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4. OBJECTIVES
Numerical modeling of a 2D Vertical Axis Wind Turbine
CFD analysis of various performance parameters
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10. MESH GENERATION (Total Structure Domain)
Nodes: 112929, Elements: 74532
Nature of the element: Quad
The first cell height used such that they y+ values from the flow solutions did not exceed 1
and the criterion is used to refine the mesh for a thickness equivalent to y+=30.
The skewness of the cells such that the maximum is observed to be less than 0.6
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12. ASSUMPTIONS
The incompressible, unsteady Reynolds Averaged Navier Stokes (URANS)
equations are solved using finite volume method.
The RNG k-ε model is adopted for the turbulence closure with standard wall
functions on Near-wall treatment.
A Sliding Mesh technique is used to rotate the rotor blade.
Intensity of inlet and outlet turbulence is fixed to 5% and turbulence viscosity
ratio 10
The unsteady Reynolds Average Navier Stokes equations are make out applying
the green-gauss cell based gradient option.
The SIMPLE pressure-based solver is selected having a second order implicit
transient formulation for better result. All of the solution variables are
calculated with second order upwind discretization scheme.
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13. MATHEMATICAL FORMULA
• Theoretical power, Pt=
1
2
∗ 휌퐴V3
• Practical power, Pa = Tω
• Torque, 푇 =
1
2
휌퐴CtV2
• Angular velocity, 휔 =
휆푉
푅
1
2
• Power co-efficient, Cp= Tω/(
휌퐴V3 )
Where, T= Torque (Nm)
A= Swept area (m2)
=2Rl
R= Rotor radius (m)
V= Free stream velocity (m/s)
ω= Angular velocity (rpm)
ρ= Density of air (kg/m3)
λ= Tip speed ratio
Ct= Torque Co-efficient
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15. RESULTS
2.00E+00
1.50E+00
1.00E+00
5.00E-01
0.00E+00
-5.00E-01
-1.00E+00
0 50 100 150 200 250 300 350 400
Torque coefficient, Ct
Azimuthal angle,θ
Figure 1: Torque coefficient vs Azimuthal angle for tip speed ratio (λ=2.0)
6.00E+00
5.00E+00
4.00E+00
3.00E+00
2.00E+00
1.00E+00
0.00E+00
-1.00E+00
-2.00E+00
0 50 100 150 200 250 300 350 400
Torque coefficient, Ct
Azimuthal angle,θ
Figure 2: Torque coefficient vs Azimuthal angle for tip speed ratio (λ=4.5)
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16. RESULTS (Cont’d)
Figure 3: Power co-efficient vs Tip speed ratio for 9 m/s
* Biadgo Mulugeta Asressa, Simonović Aleksandarb, Komarov Draganb, Stupar Slobodanb “Numerical and Analytical Investigation
of Vertical Axis Wind Turbine”, FME Transactions 2013, vol. 41, iss. 1, pp. 49-58
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18. CONCLUSION
In this thesis, a 2-D numerical analysis has been completed using sliding mesh
technique, to predict the efficiency or power co-efficient of vertical axis wind
turbine
From the performance curve, an optimum power co-efficient 0.34 is obtained at
tip speed ratio 4.5
This results may helpful for practical implementation of vertical axis wind
turbine
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19. REFERENCES
[1] Sathyajith, M, “Wind Energy Fundamentals, Resource Analysis and Economics,” Springer-Verlag
Berlin Heidelberg, Netherlands, 2006.
[2] Claessens, M.C., “The Design and Testing of Airfoils for Application in Small Vertical Axis Wind
turbines,” Delft University, November 2009.
[3] Louis Angelo Danao, Jonathan Edwards, Okeoghene Eboibi , Robert Howell, “A numerical
investigation into the influence of unsteady wind on the performance and aerodynamics of a
vertical axis wind turbine,” Proceedings of the World Congress on Engineering 2013 Vol III, WCE
2013, July 3 - 5, 2013, London, U.K.
[4] Asress Mulugeta Biadgo, Aleksandar Simonovic, Dragan Komarov, Slobodan Stupar, “Numerical
and Analytical Investigation of Vertical Axis Wind Turbine,” FME Transactions (2013) 41, pp. 49-58.
[5] Chao Li, Songye Zhu, You-lin Xu, Yiqing Xiao, “2.5D large eddy simulation of vertical axis
wind turbine in consideration of high angle of attack flow,” Renewable Energy, Volume 51, March 2013,
pp 317-330.
[6] Naveed Durrani, Haris Hameed, Hammad Rahman and Sajid Raza Chaudhry, “A detailed
Aerodynamic Design and analysis of a 2D vertical axis wind turbine using sliding mesh in CFD,”
49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition
4-7 January 2011, Orlando, Florida.
[7] Marco Raciti Castelli, Stefano De Betta and Ernesto Benini, “Effect of Blade Number on a Straight-
Bladed Vertical-Axis Darreius Wind Turbine”, World Academy of Science, Engineering and Technology
61 2012.
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