The influence of a composite duct on the hydrodynamic and vibration characteristics of a pump-jet propulsor

To address the lightweight and vibration reduction needs of pump-jet propulsors, this study proposes the use of carbon fiber-reinforced composites （CFRC） in propulsor ducts.

First, a two-way CFD/FEM fluid-structure interaction （FSI） method was developed to capture structural responses caused by hydrodynamic forces. This enabled a systematic analysis of the effects of structural deformation on both hydrodynamic performance and shaft excitation characteristics. Subsequently, a duct model was developed to investigate the impact of the composite material on hydrodynamic performance, vibration transmission mechanisms, and structural responses.

Composite ducts exhibited structural deformations of 10⁻⁷ m, indicating a negligible impact on hydrodynamic performance. The natural frequencies of the first four wet modes showed a 65.3%—80.2% reduction compared to the corresponding dry modes. Vibration analysis revealed a 1.0533 dB reduction in total acceleration level at stator-duct connections compared to bronze alloy ducts, though a slight rebound in vibration performance was observed under internal surface excitation.

The study strongly confirms the role of composites in lightweight design, vibration reduction, and performance optimization, providing a basis for propulsor design.