Abstract
The generation of tip vortex cavitation (TVC) is a common phenomenon in marine propellers. Therefore, it is important to find a way for the effective suppression of TVC. Based on the enlightenment of bionics, a propeller with winglets was numerically investigated by using a large eddy simulation (LES) model and the commercial software STAR-CCM+. Various variables, such as mesh size, number of prism layers, vapor properties and time step, were analyzed using the benchmark MAU5-80 propeller. The open water characteristics calculated for the benchmark propeller were compared with experimental data. The meshes in the region of the tip vortex wake were refined. The power spectral density (PSD) of the thrust coefficient and axial velocity were investigated. The comparison of TVC between the benchmark propeller and the propeller with winglets was studied with the Q-criterion, helicity and volume fraction of the vapor. The strength of the tip vortex wake is weakened by winglets; therefore, the presence of winglets leads to a reduction in vapor volume, which in turn alleviates TVC.
Highlights
The tip vortex cavitation (TVC) of marine propellers has become an increasingly interesting issue for marine engineers, because of its first appearance in the cases of cavitation, and as a major source as a sound pressure level contributor and in cavitation erosion [1,2]
The results indicate that the bionic rudder with a fishtail section increases the effective rudder force by approximately 10%, and improves the maneuverability of the Very Large Crude Oil Carrier with a 30% reduction in Energy Efficiency Design Index compared to a conventional rudder
The length of the helicity of the winglet-propeller in the direction of the propeller axis was shortened compared to the benchmark propeller
Summary
The tip vortex cavitation (TVC) of marine propellers has become an increasingly interesting issue for marine engineers, because of its first appearance in the cases of cavitation, and as a major source as a sound pressure level contributor and in cavitation erosion [1,2]. Muscari et al [5] analyzed wall pressure spectra that related to the evolution of a tip vortex They disclosed the non-obvious behavior of loading on the rudder that could be associated with undesirable, unsteady loads. Baek et al [7] studied the influence of the advance ratio on tip vortex of a marine propeller. The results indicate that the bionic rudder with a fishtail section increases the effective rudder force by approximately 10%, and improves the maneuverability of the Very Large Crude Oil Carrier with a 30% reduction in Energy Efficiency Design Index compared to a conventional rudder. Based on the winglets of avian wings, Ghassemi et al [22] numerically studied the influence of the rake angle of the blade tip on the open water characteristics and sound pressure level (SPL) around marine propellers. The LES turbulence model is used to numerically study a propeller with winglets
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
