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Lift Augmentation for Vertical Axis Wind Turbines
Gerald M Angle II, Franz A Pertl, Mary Ann Clarke, James E Smith
Pages - 430 - 442     |    Revised - 30-11-2010     |    Published - 20-12-2010
Volume - 4   Issue - 5    |    Publication Date - December 2010  Table of Contents
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KEYWORDS
Circulation Control, Wind Energy, Vertical Axis Wind Turbine
ABSTRACT
The concept of harnessing wind power has been around for centuries, and is first recorded by the Persians in 900 AD. These early uses of wind power were for the processing of food, particularly grinding grains, and consisted of stationary blades around a horizontal axis, the precursor to today’s horizontal axis wind turbines (HAWT). Technology for these wind mills was essentially the same until the 1930’s when advances in aircraft propeller theories were applied to the blades of the turbine. During this development period, which has since remained basically unchanged, the design push was for increasingly larger propellers requiring heavy and costly transmissions, generators, and support towers to be installed. An alternative concept to the HAWT was developed by Georges Darrieus [5], which utilized a vertical shaft and is known as a vertical axis wind turbine (VAWT). The scientific development of the concept did not gain strong attention until the 1970’s due to the perceived low efficiency of this style. This perception was due in part to the portion of the blade’s rotary path that is adverse to the generation of power. This efficiency loss can be minimized by the mechanical movement of the blade, relative to the airflow during the upwind portion of the blades’ rotational path. Since, circulation control can alter the forces generated by an airfoil, it could be used to increase the efficiency of a VAWT by increasing the torque produced on the downwind portion of the path, while removing the need for a physical change in angle of attack. With the recent upturn in petroleum costs and global warming concerns, interest in renewable energy technologies have been reinvigorated, in particular the desire for advanced wind energy technologies, including the application of lift augmentation techniques. One of these techniques is to utilize circulation control to enhance the lifting capacity of the blades based on the location of the blade in the turbine’s rotation. Though this technology can be applied to any wind turbine, whether horizontal or vertical axis, this paper focuses on the application of circulation control for VAWT’s due primarily to reduced hardware complexities and to increase the performance of this design thus helping to level the playing field between the two styles. This performance enhancement coupled with the ability to locate the primary components near the ground allows for easier installation, troubleshooting, maintenance, and future improvement of the circulation control sub-system. By varying the circulation control performance with the blade position, the coefficient of performance, Cp, of the wind turbine can be altered. This variation in Cp resembles a change in the effective solidity factor, the non-dimensional characteristic that accounts for the number of turbine blades, chord length, and turbine radius. The solidity factor is typically used in the design of a wind turbine with its peak performance occurring at various tip speed ratios, at different solidity factors. Prior to the construction of physical models, analytical methods, namely a vortex model, was used to estimate the performance enhancement potential of the blade force augmentation via circulation control. These results were then used to construct and test a wind tunnel blade section model to obtain lift and drag values for a full range of rotational angles. These results were then supplied to the vortex model which indicated that through the addition of circulation control to the blades of a vertical axis wind turbine an approximately 20% improvement in the annual energy production, and consequently the capacity factor, could be achieved.
CITED BY (4)  
1 Lowery, A. D., Arnold, A. M., & Smith, J. E. Meeting And Taking Advantage Of The Market Challenges For The Future Of Wind Power.
2 Pope, K., Wang, Z. L., Secnik, E., & Naterer, G. F. Transient Airfoil Aerodynamics of Vertical Axis Wind Turbines CCTC 2013 Paper Number 1569694747.
3 Woods, L. D. (2013). Simulation of VAWT and Hydrokinetic Turbines with Variable Pitch Foils (Doctoral dissertation, Boise State University).
4 Shires, A., & Kourkoulis, V. (2013). Application of circulation controlled blades for vertical axis wind turbines. Energies, 6(8), 3744-3763.
1 Google Scholar 
2 Academic Journals Database 
3 CiteSeerX 
4 refSeek 
5 ResearchGATE 
6 Libsearch 
7 Scribd 
8 PdfSR 
9 PDFCAST 
1 Georges Jean Marie Darrieus, "Turbine Having Its Rotating Shaft Transverse to the Flow of the Current," 1,835.018, December 1931.
2 K.A. Kuhlke, "An Experimental Investigation of the WVU Straight Bladed Darrieus Wind Turbine," Morgantown, WV, MS Thesis 1978.
3 P.G. Migliore, "A Free-Vortex Model with Numerical Solution for the Unstead Lifting Characteristics of Straight Bladed Darrieus Wind Turbines," Morgantown, WV, Ph.D. Dissertation 1978
4 P. G. Migliore, W. P. Wolfe, and R. E. Walters, "Aerodynamic Tests of Darrieus Turbine Blades," 1980.
5 J. H. Strickland, B. T. Webster, and T. Nguyen, "A Vortex Model of the Darrieus Turbine: An Analytical and Experimental Study," Alburquerque, NM, 1980.
6 N.C.K. Pawsey, Development and Evaluation of Passive Variable-Pitch Vertical Axis Wind Turbines. Diss. New South Wales: University of New South Wales, 2002.
7 David McGrain, Gerald M Angle II, Jay P Wilhelm, Emily D Pertl, and James E Smith, "Circulation Control Applied to Wind Turbines," , San Francisco, CA, USA, 2009.
8 ] B.G. Newman, "The Deflexion of Plane Jets by Adjacent Boundaries - Coanda Effect," in Boundary Layer and Flow Control, Vol. 1.: Pergamon Press, 1961, p. 232.
9 R. A. Churchill, "Coanda Jet Around a Cylinder with an Interacting Adjacent Surface," Morgantown, WV, Ph.D. Dissertation 1992.
10 J. P. Ambrosiani, "Analysis of a Circulation Controlled Elliptical Airfoil," Morgantown, WV, Ph.D. Dissertation 1971.
11 R.J. Englar, "Two-Dimensional Subsonic Wind Tunnel Tests of Two 15-Percent Thick Circulation Control Airfoils," Tech. Note AL-211 1971.
12 R. J. Kind, "A Calculation Method for Circulation Control by Tangential Blowing Around a Bluff Trailing Edge," Aeronautical Quarterly, p. Vol. XIX, 1968.
13 R J Kind and D J Maull, "An Experimental Investigation of a Low-Speed CirculationControlled Aerofoil," Aeronautical Quarterly Vol. XIX, pp. 170-182, May 1968.
14 Danny P. Myer, "An Experimental Investigation of a Circulation Controlled Cambered Elliptical Airfoil with a Rounded Trailing Edge," Morgantown, WV, MS Thesis 1972.
15 E.H. Gibbs, "Analysis of Circulation Controlled Airfoils," Morgantown, WV, Ph.D. Dissertation 1975.
16 ] J. L. Loth and M. Boasson, "Circulation Contol STOL Wing Optimization," Journal of Aircraft, pp. Vol. 21 No. 2 pp. 128-134, 1983.
17 Gregory S. Harness, "An Experimental Investigation of a Circulation Controlled Cambered Elliptical Airfoil," Morgantown, WV, MS. Thesis 1970.
18 Jay P. Wilhelm, "Power Envelope Expansion using a Solidity Matching Scheme for a Circulation Controlled Vertical Axis Wind Turbine," Morgantown, WV, PhD Dissertation 2010.
19 C. Trevelyan, "Application of Circulation Control Aerofoils to Wind Turbines," Leicestershire, UK, Ph.D. Dissertation 2002.
Dr. Gerald M Angle II
West Virginia University - United States of America
Gerald.Angle@mail.wvu.edu
Dr. Franz A Pertl
West Virginia University - United States of America
Dr. Mary Ann Clarke
West Virginia University - United States of America
Professor James E Smith
West Virginia University - United States of America