Performance study of podded propulsors with varied geometry and azimuthing conditions

• Main Author: Islam, Mohammed Fakhrul, 1977-
• Other Authors: Memorial University of Newfoundland. Faculty of Engineering and Applied Science
• Format: Thesis
• Language: English
• Published: 2009
• Subjects: Propellers; Ships > Hydrodynamics; Underwater propulsion > Mathematical models; Newfoundland studies; University of Newfoundland
• Online Access: http://collections.mun.ca/cdm/ref/collection/theses4/id/76940

Thesis (Ph.D.)--Memorial University of Newfoundland, 2009. Engineering and Applied Science Includes bibliographical references (leaves 199-209) The current research investigates the performance of podded propulsors with varied geometry at different azimuthing conditions for pusher and puller configurations in open water. -- In order to determine the prominent geometric parameters and to establish their effects on the hydrodynamic performance, the first part of the research concentrated on the geometry of pusher- and puller-podded propulsors. This experimental study consisted of investigating five geometrical parameters and their effects on propeller thrust, torque and efficiency, unit thrust and efficiency of podded propulsors. The work used a factorial design (a design of experiment technique) and analysis approach to study these effects. -- The second part of the research focussed on the hydrodynamic properties of the podded propulsors in static and dynamic azimuthing conditions. This study implemented two investigations using two separate experimental apparatus. In the first investigation, two podded propulsors were tested to measure the forces and moments on the propeller and on the unit at different static azimuthing angles within the range of-30° to 30°. In the second investigation, a separate dynamometer system was used to measure forces and moments of a model pod unit at different static and dynamic azimuthing conditions within the range of 0° to 360°. An additional study evaluated the effects of azimuthing rate and propeller shaft speed on the performance parameters under consideration at dynamic azimuthing conditions. -- The study of pods with varied geometry showed that the geometric parameters have noticeable effect on propulsive characteristics of the propulsor. The analysis provided valuable information to the podded propulsor designers. In static azimuthing conditions in the range of+30° to -30°, the propeller and unit performance coefficients changed with the change of propeller loading and azimuthing angles. In the dynamic azimuthing study, the coefficients of the propeller and the pod unit showed a strong dependence on the propeller loading and azimuthing angle. Further, these results can be used as a base for validation of numerical modelling. -- The uncertainty analysis of the measurements provided strong evidence that the presented results revealed the true performance characteristics of the model scale podded propulsors under consideration.