Research On The Entrained Water Effect Of Propeller And The Vibration Performance Of Propulsion Shafting Under Ice Impact

As the Arctic ice area decreases, Arctic waterways, energy and mineral resources prompt the development of ice navigation ship. The Arctic shipping voyage of China increased significantly, due to ice-water mixed environment in polar waters is extremely complex, The higher requirements are put forward for the safety of the ship. Considering the propeller works outside of the hull, it will collide ice inevitably, and thus the impact load is transmitted to the ship propulsion shafting, causing shaft vibration, as it is the core of the system of ship power plant, its damage will lead to the fall of the ship traffic capacity and safety; at the same time, the vibration inherent characteristic of ship propulsion shafting is affected by propeller attached water effects, which alse will change in ice-water. For these reasons, the vibration performance of propulsion shafting in ice-ship is studied in the paper. The results in the research would provide a reference for the the entrained water effect of propeller and the shafting vibration.In this paper, numerical method, empirical formula are applied to analyze the attached water effects of propeller in the open water, the feasibility of the numerical analysis method is verified, comparison with the CCS empirical coefficient, reasonable amendment suggestions are provided for the coefficient; the attached water effect of propeller in ice loads is analyzed at different cutting angles by this numerical method.In this paper, the literature data, the approximate calculation methods and numerical methods are applied to analyze the inherent characteristics of four kinds of shaft vibration, the feasibility of the numerical methods of shafting vibration is verified; the natural frequency of not considering the attached water, considering attached water and considering ice attached water are analyzed and compared.In this paper, the related loads of shaft torsional vibration time-domain response calculation in ice impact are emulated and analyzed, combined with numerical time-domain calculation method and the frequency domain results in shaft torsional vibration calculations, the reasonability of the numerical time-domain method is verified; to the normalfire and single cylinder misfire for the host, according to the ice load excitation conditions provided in CCS rules, the shaft torsional vibration domain response is analyzed in the three factors aspects of engine speed, different single cylinder misfire, phase angle between host load and ice load.