Hydrodynamic Characteristics of a Propeller in Open Water, Ducted and in a Semi-Tunnel Conditions - a Case Study on Small Waste Collecting Vessel

This paper presents a comparison of the hydrodynamic characteristics of an open water propeller, a propeller in a duct and a propeller in a tunnel, obtained using the four quadrant methodology, for low-velocity small vessels. The study explored how the hydrodynamic characteristics of a B-Wageningen series propeller operating with energy saving devices change with all possible parameters of motion. Tests of the propeller operating in a duct were then expanded to include a new design solution with additional blades directing the flow inside the duct. The results were obtained by performing CFD calculations, based on model-scale unsteady RANS simulations with a sliding grid approach. The calculations covered selected combinations of the propeller RPM and advance speed. During the tests, the thrust coefficients and torque coefficients were determined for the tested solutions. The merit coefficient was introduced in order to determine the most efficient design solution by means of the greatest thrust-torque ratio.