Influence of bearings on the open water performance of a rim-driven thruster

Abstract

The rim-driven thruster (RDT) represents an important advance in the marine propulsion system. Its innovative structure introduces several outstanding advantages but also rises some major challenges. This paper aims to investigate the influence of bearings on the rim-driven thruster in terms of hydrodynamic performance with computational fluid dynamics. Bearing parameters including the shape of the contact surface and the number of grooves are considered. The simulation results indicate that the presence of the bearings in the gap has an influence on the overall performance of the thruster by changing the flow regime in the gap and the interactions between different components in the RDT. The shape of the bearings also exhibits significant impacts: the conical bearings, even though with simpler structure, shows the worst performance among all three bearing configurations, while the ordinary bearings always have a higher hydrodynamic efficiency than the other two bearing configurations under all considered advance coefficients. The difference in efficiency at the design point can reach up to 3% between the ordinary and conical bearing configurations.