A study of Energy Saving Devices for Oshima Bulk Carrier, C2591-21CT17-RAP02 - Tests No. 11 ÷ 30

Experiments have been carried out at CNR-INSEAN of a Bulk Carrier model equipped alternatively with four Preswirl Duct appendages. The ducts are energy saving devices (ESD) mounted on the stern boss just upstream of the propeller, capable to generate pre-swirled flow into the propeller against the propeller rotating direction. This generally improves the propulsive efficiency and results in a power reduction. The tested Ducts differs each other in number and form of the bladed stators, and extension of the ducts. The reference configuration used to establish the base line is a 5-bladed pre-swirl stator. A reduction of the power consumption of about 2% was evaluated at the Design Load condition at the speed corresponding to 14 knots.