Data Analysis for a Model Podded Propulsor in Ice (Pusher Mode)

• Main Author: Simmonds, Michael
• Format: Report
• Language: English
• Published: National Research Council Canada 2009
• Subjects: Propeller; Advance Coefficient; Non-Dimensional Thrust Coefficient; Non-Dimensional Torque Coefficient; Exceedance Probability; Sea ice
• Online Access: https://dx.doi.org/10.4224/18227306; https://nrc-publications.canada.ca/eng/view/object/?id=9424bd78-6f0e-47d5-8898-f879709ebe08

Non-hospitable areas are frequently being explored for new energy resources and most of these places are ice covered. Understanding the interactions between a ship’s propeller and sea ice is fundamental in the production and manufacturing of podded propulsors. The test facilities here at IOT were used to conduct experiments whereby a model-podded propeller was used in the ice tank and propeller-ice interaction parameters were measured and recorded by the use of dynamometers. Tests were conducted using the two operating conditions, (tractor and pusher), different depths of cut, varying azimuth angles, and a range of propeller rotational speeds and carriage velocities. The analysis of ice loads in pusher mode is different to that of tractor mode because of the un-uniform ice conditions experienced during pusher mode. The acquired results must be represented in either individual blade angular positions or individual revolutions. This can be easily done with computer programs such as Sweet. Parameters, such as advance coefficient, thrust coefficient, and torque coefficient, can be calculated from the newly represented data. Plotting these parameters against an exceedance probability can easily show that as the depth of cut, azimuth angles and advance coefficients increase, the maximum torque values also increase. After setting an appropriate return period of the probability, deterministic values of ice loads, (here we used shaft torque), can be provided depending on the design criteria (such as 100-year load).