Numerical Investigation of Contra Rotating Propeller Efficiency on Ferries through CFD Simulation

Abstract

This research focuses on the pressing issues of global warming and fossil fuel depletion. It discusses the International Maritime Organization's (IMO) proactive approach to these challenges by introducing the Energy Efficiency Design Index (EEDI). The EEDI is a pioneering initiative that emphasizes the development of propulsion systems incorporating Energy Saving Devices (ESD). A vital feature of this research is the exploration of the contra-rotating propeller, a propulsor configuration that promises higher efficiency than conventional single-propeller propulsion systems. The unique advantage of the contra-rotating propeller lies in its ability to recover rotational energy in the propeller slipstream. This energy recovery produces higher thrust with torque equivalent to conventional systems, thereby enhancing efficiency. The research employed Computational Fluid Dynamics (CFD) software to determine the impact of contra-rotating propellers on propeller efficiency in ferry propulsion systems. The study aimed to identify an optimal propeller placement and diameter combination to maximize efficiency. The findings of this research are promising. The use of contra-rotating propellers on ferry boats resulted in a significant increase in propeller efficiency. Specifically, efficiency increased by 6.498% on model 2 with a diameter ratio of 1:0.87. Similarly, in model 1 with a diameter ratio of 1:1, efficiency increased by 3.374%. These results highlight the potential of contra-rotating propellers in enhancing the energy efficiency of maritime propulsion systems. Therefore, this research provides valuable insights for designing future energy-efficient maritime vessels.