Propulsion Performance and Hub Vortex Reduction on Various Propeller Boss Cap Fins Designs

The call for improvement in ship energy efficiency for sustainable shipping leads to emerging development of energy saving devices. Amongst all devices, propeller boss cap fins has gained much interest due to their benefit in improving the propulsive efficiency and ease of installation. However, past researches in the field have disclosed that each design parameter behaves differently in sharing the increment of overall propulsion performance. This study presents the optimization of propeller boss cap fins design parameter by using CFD analysis. The initial main geometrical parameters opted for the study are the significant ones suggested by previous researches. Various design alternatives using the parameters have been simulated and the influences on the propulsion performance have been analyzed. The examination carried out revealed that each design configuration contributes to the net thrust and torque qualities in various ways. The optimum configuration achieves an efficiency up to 3.23% compared to the conventional propulsion system. Observation on the wake flow downstream the device indicates that the additional fins from the device restrained the flow downforce, weakened the hub vortex, and in return boosted up the propulsion system efficiency. As a standalone retrofit using the device is proven effective, a combined retrofit with other devices would be more fruitful.