The Use of Twist-Coupled Blades to Enhance the Performance of Horizontal Axis Wind Turbines

This paper reviews issues related to the use of aeroelastic tailoring as a cost-effective, passive means to shape the power curve and reduce loads. Wind turbine blades bend and twist during operation, effectively altering the angle of attack, which in turn affects loads and energy production. It is possible to build a small amount of desirable twisting into the load response of a blade with proper asymmetric fiber lay up in the blade skin. The tailored twisting can create an aeroelastic effect that has payoff in either better power production or in vibration alleviation, or both. Several research efforts have addressed different parts of this issue. Research and development in the use of aeroelastic tailoring on helicopter rotors is reviewed. Potential energy gains as a function of twist coupling are reviewed. The effects of such coupling on rotor stability have been studied and are presented. Fatigue damage estimates due to turbulent inflow have been computed for rotors employing several different control schemes, with and without twist-coupled blades. Energy otput and maximum loads are also computed and compared.

[1]  S. M. Rock,et al.  Effects of Blade Bending on Aerodynamic Control of Fluctuating Loads on Teetered HAWT Rotors , 1995 .

[2]  M. W. Davis,et al.  Experimental Verification of Helicopter Blade Designs Optimized For Minimum Vibration , 1988 .

[3]  P. W. Carlin,et al.  Results from the NREL Variable-Speed Test bed , 1998 .

[4]  R. E. Hutton,et al.  Effect of Spanwise and Chordwise Mass Distribution on Rotor Blade Cyclic Stresses , 1956 .

[5]  R. B. Taylor,et al.  Helicopter Vibration Reduction by Rotor Blade Modal Shaping , 1982 .

[6]  Peretz P. Friedmann,et al.  Development of a structural optimization capability for the aeroelastic tailoring of composite rotor blades with straight and swept tips , 1992 .

[7]  Paul S. Veers,et al.  Performance of twist-coupled blades on variable speed rotors , 2000 .

[8]  A. H. P. Swift,et al.  Dynamics of an experimental two bladed horizontal axis wind turbine with blade cyclic pitch variation , 1981 .

[9]  W. E. Holley,et al.  Scale and Lag Effects on Control of Aerodynamic Power and Loads on a HAWT Rotor , 2001 .

[10]  Ranjan Ganguli,et al.  MULTI-OB JECTIVE OPTIMIZATION OF A COMPOSITE HELICOPTER ROTOR , 1994 .

[11]  P. G. Migliore,et al.  ENHANCED PERFORMANCE OF HAWTS USING ADAPTIVE BLADES , 1996 .

[12]  Inderjit Chopra,et al.  Aeroelastic Stability Analysis of a Composite Rotor Blade , 1985 .

[13]  P. Shanthakumaran,et al.  Aeroelastic tailoring of rotor blades for vibration reduction in forward flight , 1983 .

[14]  Inderjit Chopra,et al.  Design sensitivity analysis for an aeroelastic optimization of a helicopter blade , 1987 .

[15]  Cheng-Huat Ong,et al.  Design, Manufacture and Testing of A Bend-Twist D-Spar , 1999 .

[16]  Peretz P. Friedmann,et al.  Optimum design of rotor blades for vibration reduction in forward flight , 1984 .

[17]  George W. Brooks,et al.  A dynamic-model study of the effect of added weights and other structural variations on the blade bending strains of an experimental two-blade jet-driven helicopter in hovering and forward flight , 1955 .

[18]  Mark W. Davis,et al.  Wind Tunnel Tests of Helicopter Blade Designs Optimized for Minimum Vibration , 1989 .

[19]  Eduard Muljadi,et al.  Effects of turbulence on power generation for variable-speed wind turbines , 1997 .

[20]  Don W. Lobitz,et al.  Load mitigation with twist-coupled HAWT blades , 1999 .

[21]  T. D. Ashwill,et al.  Aeroelastic effects in the structural dynamic analysis of vertical axis wind turbines , 1986 .

[22]  Inderjit Chopra,et al.  Aeroelastic optimization of a composite helicopter rotor , 1992 .

[23]  Paul S. Veers,et al.  AEROELASTIC BEHAVIOR OF TWIST-COUPLED HAWT BLADES , 1998 .

[24]  David Infield,et al.  Design criteria for passive pitch control of wind turbines using self-twisting blades , 1995 .

[25]  Paul S. Veers,et al.  Aeroelastic tailoring in wind-turbine blade applications , 1998 .

[26]  Mark W. Davis,et al.  Application of Design Optimization Techniques to Rotor Dynamics Problems , 1986 .

[27]  P. C. Klimas.  Tailored airfoils for Vertical Axis Wind Turbines , 1984 .

[28]  E. Smith,et al.  Formulation and evaluation of an analytical model for composite box-beams , 1991 .

[29]  W. J. Bohnhoff,et al.  Utilizing object-oriented design to build advanced optimization strategies with generic implementation , 1996 .

[30]  Inderjit Chopra,et al.  Aeroelastic optimization of a helicopter rotor , 1989 .

[31]  Don W. Lobitz.  A NASTRAN-based computer program for structural dynamic analysis of Horizontal Axis Wind Turbines , 1995 .

[32]  N. Kelley.  Full vector (3-D) inflow simulation in natural and wind farm environments using an expanded version of the SNLWIND (Veers) turbulence code , 1992 .

[33]  R. H. Miller,et al.  Helicopter Blade Vibration and Flutter , 1956 .

[34]  J. L. Tangler,et al.  NREL airfoil families for HAWTs , 1995 .

[35]  Paul G. Migliore,et al.  Maximizing Energy Capture of Fixed-Pitch Variable-Speed Wind Turbines , 2000 .

[36]  Inderjit Chopra,et al.  Aeroelastic Tailoring of Composite Couplings and Blade Geometry of a Helicopter Rotor Using Optimization Methods , 1997 .

[37]  L. A. Schmit,et al.  NEWSUMT: A FORTRAN program for inequality constrained function minimization, users guide , 1979 .