Bell-Metha Power Augmented Savonius turbine as Take-off in OWC Systems

The present paper deals with the study of ducted Savonius turbine performance to be used as power take-off in oscillating water column systems equipped with a power booster. Two converging sections with a Bell-Metha profile have been used to increase the mass flow rate on the active side of the turbine while masking the resistant part. The Bell-Metha profile was chosen with the aim of reducing vortices immediately upstream of the turbine, avoiding both disturbance and energy loss. A laboratory scale Savonius turbine with a diameter of 0.09 m with an aspect ratio of 1 and an overlap ratio of 1/3 was tested. Performance was tested using a laboratory scale oscillating flow simulator. All tests were performed at fixed air velocity of 5 m/s. Based on the results, it is possible to state that ducted turbine with power augmenter performance is higher than plain ducted turbine ones, at all tip speed ratios.