Integrated Design of Propeller and Multiple Energy Saving Devices with Consideration of Their Interaction
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In recent years, the EEDI (Energy Efficiency Design Index) and the EEXI (Energy Efficiency Existing Ship Index) have been established as ship performance regulations. Shipyards and shipowners now place greater focus on energy saving than before. Many naval architects have conducted research into improvement of propulsion performance. For example, various energy-saving devices (hereinafter, referred to as ESD), such as the ECO-Cap, Ultimate Rudder Bulb and Neighbor Duct, have been developed to reduce fuel oil consumption. In addition, these ESDs have been shown to enhance propulsion performance. However, it is important to consider the interaction of propeller with multiple ESDs in order to achieve greater performance improvements, as the effectiveness of ESDs also depends on propeller design. This study investigated the interaction of propellers and multiple ESDs by conducting CFD (Computational Fluid Dynamics) analysis. Furthermore, the integrated design, which consider the interaction of propeller and ESDs was carried out using CFD for an actual merchant ship, and its effectiveness was confirmed through a sea trial. The sea trial reveals the energy-saving performance of the integrated design scheme of the propeller and multiple ESDs developed in this study. An energy-saving effect of approximately 9%, as estimated from the model test at the design draft, is indicated based on the power curve obtained during the sea trial.