Effect of partial blockage of air duct outlet on performance of OWC device

Abstract

The use of a Savonius rotor as turbine for an oscillating water column (OWC) is demonstrated. The effect of tuning the OWC using turbine duct blockage is also studied for different wave conditions. A horizontal turbine section OWC employing a Savonius rotor was tested by varying the opening of OWC exit (0%, 25%, 50%, 75% and 100%) to study the behavior and performance of the device. The OWC model was tested at water depth of 0.29 m at frequencies of 0.8, 0.9 and 1.0 Hz while the exit openings are varied. The static pressure, dynamic pressure, rotational speed of the Savonius rotor and the coefficient of power are presented as results. The OWC with exit opening of 25% showed greater performance in terms of rotational speed and C_P compared to OWC with other exit opening percentages. This proves the ability of the OWC to be tuned by regulating flow in the turbine duct.

Keywords

oscillating water column / wave energy converter / wells turbine / impulse turbine / Savonius rotor

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