Productivity of ocean-wave-energy converters: Turbine design

A study was undertaken to identify which of a range of advanced Wells turbine configurations would maximize wave power productivity. The productivity is estimated of a monoplane with fixed guide vanes, a monoplane with variable-pitch blades, and a high- and low-solidity biplane with counterrotating rotors. Two control mechanisms are investigated for the variable pitch configuration. Raleigh distributions based on a mean annual pneumatic power rating of 500 kW are utilized to generate the short and long-term variations of input power to be matched with experimental turbine performance data obtained from a steady-state test rig. It was found that productivity was relatively insensitive to turbine configuration but that a low-solidity counterrotating turbine had the best performance characteristic providing high peak efficiency and gradual onset of stall.