THE ENERGY-CONVERSION PERFORMANCE OF SEVERAL TYPES OF WELLS TURBINE DESIGNS

Several types of single-plane and multiplane Wells turbines are invest igated and compared. The turbines' aerodynamic losses and overall perf ormances are presented and two successful methods of swirl energy reco very are studied in detail. Guide vanes were fitted to a monoplane tur bine whereas the rotors of a biplane turbine were contra-rotated. A do uble-shaft biplane turbine was also tested. The contra-rotating turbin e had an operational range which was similar to that of the monoplane turbine with guide vanes, achieved a similar peak efficiency, but perf ormed better in the post-stall region and also was found to be able to accommodate a much higher pressure-flow ratio.