Wind tunnel measurements for the characterization of a small scale monoplane Wells turbine

Abstract

In the field of wave energy harnessing, Oscillating Water Column (OWC) devices are nowadays a consolidated technology. In OWC energy converters, waves generate an oscillating flow, whose energy can be effectively captured, for instance, by means of self-rectifying Wells turbines. In the design of Wells turbines, main issues are the improvement of their peak efficiency and the widening of their operational range. In order to reach these goals, a deep knowledge of the turbine fluid dynamic performance is essential. This paper presents the results of the experimental investigation of a small scale monoplane Wells turbine, tested in an open circuit low speed wind tunnel of the suction type in order to characterize its performance in terms of non-dimensional parameters, namely, torque and pressure drop coefficients and efficiency. The prototype under investigation, with blades of constant chord and NACA0015 profile, has been designed in order to be matched with a REWEC (Resonant Wave Energy Converter) breakwater, which had been located off the beach of Reggio Calabria. The REWEC under consideration was an excellent small scale model of full scale sea wave energy conversion devices for oceanic applications. Results have been compared with previous in-field tests, showing a very good agreement.