An experimental method for model propeller-ice interaction in air: concept and first results

• Published in: Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology
• Main Authors: Bach, Constantin, Myland, Daniela
• Format: Conference Object
• Language: English
• Published: The American Society of Mechanical Engineers 2017
• Subjects: Ice loads; Ice milling; Ice model testing; Ice testing equipment; Propeller loads; Propeller-ice interaction; Ships in ice; 600: Technik; Arctic
• Online Access: http://hdl.handle.net/11420/5029

One of the aims of the German national funded research project ProEis is to develop a methodology for determination of ice loads on model propellers which will then aid in improving and developing software tools for their prediction. For this purpose, a prototype device has been designed at HSVA within this project which is used to guide defined ice floes with one degree of freedom into a model propeller where they are milled and the resulting forces and moments are measured. This paper focuses on the description of the ice feeding device and presents some first results with respect to the physical process as well as measured load characteristics. For now, experiments are conducted in absence of water in order to exclude all hydrodynamic effects. A podded propeller is used which allows measuring of shaft torque and shaft thrust. A high speed video camera is also employed to record the propeller-ice interaction process at 5000 frames per second, allowing to observe the milling process in detail. Two basic impact patterns are observed with respect to their relative load levels. When the greater part of the leading edge of the propeller strikes the ice from the top, i.e. it crushes the granular layer and cuts off a relatively large chunk of ice, the maximum shaft thrust is approximately 1.5 times as high as when the leading edge of the propeller makes contact at the front face of a floe, scraping off a thin layer of ice. Shaft torque is mostly unaffected by the type of impact. The performance of the ice feeding device and the findings of the first tests presented here are reviewed and discussed critically. Recommendations for the planning of such tests and possible improvements of the device are given.