A study of an axial-flow turbine for kinetic hydro power generation

Abstract

The ancient notion of installing turbines directly in waterways, without the use of civil structures, has been reviewed recently. In an early study conducted for the New York Power Authority (NYPA), we reached conclusions regarding the resource and types of kinetic hydroenergy conversion systems (KHECS) which could be utilized. These studies established that a kinetic hydro-energy resource sufficient to warrant the development of devices to exploit it exists in New York State. A technology assessment yielded a number of types of devices which could be practical, while criteria including efficiency, simplicity, cost-effectiveness, and near-term commercialization indicated an advantage to axial-flow propeller machines in both tidal flows and rivers. Rotor blades designed according to the Glauert theory were tested and produced the necessary high efficiency (nearly 80% of the theoretical maximum). Fixed-pitch rotor operating curves yielded good load matching with an induction generator. Since units must operate reliably underwater for extended periods, variable-blade pitch or variable-speed drive mechanisms add a degree of complexity which should be avoided, if possible. These factors have been accommodated by careful rotor design and selection of drive and generating components. The culmination of the study involves the design, fabrication, and testing of a grid-connected, full-scale prototype in New York's East River and the determination of the national resource. At the prototype level this research project incorporates various examples of environmental and other administrative permitting. The prototype experimental program is described. With respect to resource assessment, an investigation is being performed to determine which rivers of the U.S. are acceptable for KHECS utilization.