Experimental and numerical analyses of the hydrodynamic performance of propeller boss cap fins in a propeller-rudder system

Abstract

This paper presents the simulated and experimental results of propeller-rudder systems with propeller boss cap fins (PBCFs) and analyzes the hydrodynamic performance of PBCFs in propellerrudder systems. The purpose is to study the impact of PBCFs on the hydrodynamic performance of rudders. Hydrodynamic experiments were carried out on propeller-rudder systems with PBCFs in a cavitation tunnel. The experimental energy-saving effect of the PBCF without a rudder was 1.47% at the design advance coefficient J = 0.8. The numerical simulation was based on the Navier-Stokes equations solved with a sliding mesh and the SST (Shear Stress Transfer) k-ω turbulence model. After the grid independence analysis, the flow fields of an open-water propeller with and without a PBCF were compared, then the efficiencies of the propulsion systems including different rudders and the thrust coefficient K r of rudders were analyzed. The results indicate that the installation of a PBCF increases the resistance of the rudder, which results in a reduction in the energy-saving effect of the PBCF. At the design advance coefficient, the energy-saving effect of the PBCF with an ordinary rudder and a twisted rudder decreases from 1.47% to 1.08% and 1.16%, respectively; thus, it is important to factor in the rudder of a propulsion system when evaluating the energy-saving effects of PBCFs . ARTICLE HISTORY

Numerical Analysis Of Aerofoil Shape Propeller Boss Cap Fin (PBCF) To Improve Propeller Efficiency

“…There is increase in efficiency and overall reduction of power consumption by 1.8%-2%. Numerical as well as experimental investigation performed by Sun et al [13] to observe the impact of PBCF to improve propeller efficiency in propeller rudder system. Results of cavitation test represented 1.47% energy saving with PBCF in absence of rudder at an advance ratio 0.8.…”

Hydrodynamic Analysis-Based Modeling and Experimental Verification of a New Water-Jet Thruster for an Amphibious Spherical Robot

“…The experimental devices consisted of a load cell, an electronic-optic, and an analog electromagnetic current meter. Hydrodynamic experiments for thrust prediction of a propeller-rudder system were conducted in the cylinder section of a cavitation tunnel [23]. A bollard pull test of a ducted thruster was carried out to predict the thrust when blades rotated in the forward direction and in the inverse direction [24].…”

Effect of the Incline Angle of Propeller Boss Cap Fins (PBCF) on Ship Propeller Performance

“…The other function of PBCF is to eliminate the vortex phenomenon on the hub part of the rotor. It has been evidenced by Dang et al (2011), Kawamura et al (2012), Cheng and Hao-Eng (2014), Molland et al (2014), and Sun et al (2016) in research based on field studies, lab trials and computational fluid dynamic (CFD) simulations that PBCF can eliminate the vortex and improve the efficiency of ships' propellers. Considering design parameters, PBCF will influence propeller efficiency noticeably (Seo et al, 2016;Mizzi et al, 2017).…”