Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 31103
Numerical Analysis of the Influence of Airfoil Asymmetry on VAWT Performance

Authors: Marco Raciti Castelli, Giulia Simioni, Ernesto Benini

Abstract:

This paper presents a model for the evaluation of energy performance and aerodynamic forces acting on a three-bladed small vertical axis Darrieus wind turbine depending on blade chord curvature with respect to rotor axis. The adopted survey methodology is based on an analytical code coupled to a solid modeling software, capable of generating the desired blade geometry depending on the blade design geometric parameters, which is linked to a finite volume CFD code for the calculation of rotor performance. After describing and validating the model with experimental data, the results of numerical simulations are proposed on the bases of two different blade profile architectures, which are respectively characterized by a straight chord and by a curved one, having a chord radius equal to rotor external circumference. A CFD campaign of analysis is completed for three blade-candidate airfoil sections, that is the recently-developed DU 06-W-200 cambered blade profile, a classical symmetrical NACA 0021 and its derived cambered airfoil, characterized by a curved chord, having a chord radius equal to rotor external circumference. The effects of blade chord curvature on angle of attack, blade tangential and normal forces are first investigated and then the overall rotor torque and power are analyzed as a function of blade azimuthal position, achieving a numerical quantification of the influence of blade camber on overall rotor performance.

Keywords: VAWT, NACA 0021, DU 06-W-200, cambered airfoil

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1332788

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2454

References:


[1] Sheldal, R. E., Klimas, P. C., "Aerodynamic Characteristics of Seven Symmetrical Airfoil Sections Through 180-Degree Angle of Attack for Use in Aerodynamic Analysis of Vertical Axis Wind Turbines", SAND80-2114, Unlimited Release, UC-60.
[2] Stathopoulos, T., "Wind Effects on People", Proceedings of the International Conference on Urban Wind Engineering and Building Aerodynamics - Impact of Wind Storm on City Life and Built Environment, COST Action C14, Von Karman Institute, Rode-Saint- Genèse (Belgium), 2004.
[3] Jensen, A. G., Franke, J., Hirsch, C., Schatzmann, M., Stathopoulos, T., Wisse, J., Wright, N. G., "CFD Techniques - Computational Wind Engineering", Proceedings of the International Conference on Urban Wind Engineering and Building Aerodynamics - Impact of Wind and Storm on City Life and Built Environment - Working Group 2, COST Action C14, Von Karman Institute, Rode-Saint-Genèse (Belgium), 2004.
[4] Paraschivoiu, I., Wind Turbine Design: With Emphasis on Darrieus Concept, Polytechnic International Press, Montreal, 2002.
[5] Johnston. S. F. (Editor), Proceedings of the Vertical-Axis Wind Turbine (VAWT) Design Technology Seminar for Industry, April 1-3, 1980, Sandia National Laboratories, SAND80-0984, August 1980.
[6] Saeed, F., Paraschivoiu, I., Trifu, O., "Inverse Airfoil Design Method for Low-Speed Straight-Bladed Darrieus-Type VAWT Applications", 7th World Wind Energy Conference 2008: Community Power, Kingston, Ontario, Canada June 24-26th, 2008.
[7] Claessens, M. C., The Design and Testing of Airfoils for Application in Small Vertical Axis Wind Turbines, M.Sc. Thesis, Faculty of Aerospace Engineering, delft University of Technology, The Netherlands, November 9, 2006.
[8] Kadlec, E. G., "Characteristics of Future Vertical Axis Wind Turbines", Sandia National Laboratories Report SAND79-1068, Nov. 1982;
[9] Strickland, J. H., "The Darrieus Turbine: A Performance Prediction Model Using Multiple Streamtube", SAND75-0431.
[10] Simao Ferreira, C. J., Bijl, H., van Bussel, G., van Kuik, G., "Simulating Dynamic Stall in a 2D VAWT: Modeling Strategy, Verification and Validation with Particle Image Velocimetry Data", The Science of Making Torque from Wind, Journal of Physics: Conference Series 75, 2007.
[11] Bradshaw, P., Experimental Fluid Mechanics, Cambridge University Press, 1964.
[12] Fluent Inc., Fluent User-s Manual, pp. 52, 54, 59, 71, 143.
[13] Cummings, R.M., Forsythe, J.R., Morton, S.A., Squires, K.D., "Computational Challenges in High Angle of Attack Flow Prediction", 2003, Progr Aerosp Sci 39(5):369-384;
[14] Raciti Castelli, M., Ardizzon, G., Battisti, L., Benini, E., Pavesi, G., "Modeling Strategy and Numerical Validation for a Darrieus Vertical Axis Micro-Wind Turbine", IMECE2010-39548.
[15] Raciti Castelli, M., Benini, E., "Comparison of Two Airfoil Sections for Application in Straight-Bladed Darrieus VAWT", submitted for publication to: World Academy of Science, Engineering and Technology on September 28, 2011.
[16] Raciti Castelli, M., Englaro, A., Benini, E., "The Darrieus Wind Turbine: Proposal for a New Performance Prediction Model Based on CFD", Energy 36 (2011) 4919-4934.