Wind tunnel investigation of models of two diffuser design concepts is directed toward unconventional, very short, cost-effective configurations. One approach uses the energetic external wind to prevent separation of the diffuser's internal boundary layer. Another method used high lift airfoil contours for the diffuser wall shape. Diffuser model tests have indicated almost a doubling of wind power extraction capability for DAWTs compared to conventional turbines. Economic studies of DAWTs have used these test data and recent (1975) cost projections of wind turbines with diameter. The specific power costs ($/kW) for a realistic DAWT configuration are found to be lower than conventional wind turbines for very large size rotors, above 50 meters diameter, and for rotor diameters less than about 20 meters. The cost-to-benefit assessment for intermediate size rotors is affected by the uncertainty band of cost for these rotor sizes.
A test center has been established with 12 machine towers of varying descriptions and eight WTGs erected to date. Additionally, two large and three small meteorological towers have been installed as well as a small irrigation system, typical of the type commonly used throughout the country. Experience with these machines has revealed a number of operational problems, but has resulted in hardware modifications by manufacturers. The other main area of effort has been to solicit and evaluate proposals for development of 8 kW, 40 kW, and High Reliability SWECS.
Information is presented concerning wind data collections and analysis; Hart power demand and consumer usage; wind power assessment; hydro power assessment; results of preliminary economics analysis; environmental impact of wind turbines and operation in the Hart, Oceana County, Michigan area; and systems model for the Hart power system with wind turbine. (DCC)
Application of composite bearingless rotor concept to wind turbine rotor. Progress report, June 3, 1975--October 31, 1975 |
The objective of the one year program is to explore the feasibility of the Composite Bearingless Rotor (CBR) for use as a wind turbine and to evaluate several automatic control concepts designed to improve efficiency and cost effectiveness. The program consists of the design of a full-scale wind turbine, the design and fabrication of a dynamically scaled model, wind tunnel experiments, and analytical studies. To date, the design work has been completed, the model wind turbine support tower has been fabricated and assembled with a generator. The model blades and other hardware are under construction. This interim progress report contains descriptions of the full scale and model designs, a review of the performance characteristics expected of the wind turbine, and an outline of the remaining tasks of the program. Appendices are included to provide detailed information on some of the design characteristics of the model wind turbine.
Sandia Laboratories Low-Speed Wind Tunnel for Research in Atmospheric Flows and Incompressible Fluid Mechanics |
Investigation of Rotation-Induced Stresses of Straight and Curved Vertical Axis Wind Turbine Blades |