8.05 – Air Turbines

TLDR: In this paper, the authors presented the aerodynamic theory of axial-flow turbines and applied it to the Wells turbine and the impulse turbine, including their variants, in order to analyze their integration into the OWC wave energy converter.

Abstract: Air turbines are used to equip oscillating water column wave energy converters. In almost every case, self-rectifying turbines have been adopted which do not require non-return valves to rectify the reciprocating air flow induced by the water column oscillations. The most frequently used or proposed self-rectifying air turbines are the Wells turbine and the impulse turbine, both of axial-flow type. The fundamentals of the aerodynamic theory of axial-flow turbines are presented and then applied to the Wells turbine and the impulse turbine, including their variants. Information is given on methods of, and results from, air turbine model testing, as well as on self-rectifying air turbines that equipped or equip prototypes tested in the sea. The final part of the chapter is devoted to the analysis of turbine integration into OWC wave energy converter.