Improving the propulsion performance of composite propellers under off-design conditions

Abstract

Pre-deformation design can improve the propulsive efficiency of composite ship propellers under off-design conditions, where propulsive efficiency is related to the geometry of the propeller blade. Material attributes affect the deformation of composite propeller blades, suggesting that these also affect the propulsive efficiency of a pre-deformed composite propeller (PDCP) under off-design conditions. In this study, the hydrodynamic performance and structural response of composite propellers were determined and verified using computational fluid dynamics and the finite element method. The effects of elastic and shear moduli on propulsive efficiency and structural deformation were analyzed, and the influences of changing material attributes and propeller advance ratios were compared. Based on existing propeller theories, an objective function was proposed for selecting the most suitable material attribute scheme for the DTNSRDC 4383 propeller, from 18 different materials. Such a selection allows for an optimization of the comprehensive propulsive efficiency of a composite propeller through pre-deformation design. The results show that when the PDCP has an elastic modulus E = 135 GPa and a shear modulus G = 2.07 GPa, it exhibits optimal comprehensive propulsive efficiency. The findings of this study can be used in the design of composite propellers to maximize performance under a broad range of working conditions.