Numerical Study of the Hydrodynamic Performance of Rim-Driven Propulsion Featuring a Modified 19A Duct

The rim-driven propeller (RDP) is an innovative propulsion system that is primarily used in underwater vehicles and the bow thrusters of ships. In this study, the Reynolds-averaged Navier-Stokes (RANS) equations are employed together with the moving reference frame method and steady-state numerical simulations to address challenges related to applicability. The SST turbulence model is also incorporated. Initially, a Ka-Series+19A ducted propeller (DP) is considered, and the numerical results for its hydrodynamic performance are found to show a close correlation with experimental data. Notably, the thrust coefficient of the duct at low advance coefficients is high, indicating that the duct can operate efficiently under heavy load conditions. The study then focuses on the RDP, which uses the same propeller but features a distinct duct design due to its rim-driven configuration. The hydrodynamic open-water characteristics of the RDP are obtained and compared with those of the DP. The results reveal that the RDP has lower efficiency than the DP, primarily due to the gap and the presence of the rotor in the RDP. Furthermore, a detailed analysis of the pressure distribution on the surfaces of the blade and duct is presented, as well as the velocity and pressure contours at various downstream positions for both the DP and RDP. Particular attention is paid to the flow gap between the propeller and duct, along with the associated turbulence intensity.