Energy-saving Technology Research Of Existing Ship Propeller Cut

The energy crisis is more and more serious, and the globe is warmer and warmer. So the greenhouse emission from ships is given more concern. There are three sorts of solutions for energy saving and emission reduction. The technical solution aims at improving the design efficiency of the ships, the managing one aims at improving the operation efficiency of the crew, and the emission reduction solution, which based on the market, is to reduce the CO2 emission by the economic lever.Because of the economic crisis, that ships sail in lower speed to reduce the fuel consumption is common. According to the calculation, after cutting the edge of propeller under equal power, the rev is increased, but the open water efficiency and the speed both are decreased. However, the increase of the rev is quicker than the decrease of the speed. It shows that the increase of the rev is more sensitive to the cut of the propeller, which is good for improving the economical efficiency. And the relationship among propeller cut capacity with rev, efficiency and sailing speed is useful for the future propeller cut. Based on the running state of the main engine after cutting, the model of the MAN B&W 5S60MC is established, and the main running parameters under the 25%,50%,75% and 85% load are calculated. The research indicates that cutting the edge of propeller can increase the rev, reduce the oil consumption and improve the economical efficiency. In addition, the capability of lubrication and vibration are both improved after cutting. The combustion start angle, the duration of the combustion, the open and close angle of the discharge valve, and the compression ratio are optimized after cutting the edge of propeller and calculates again to make sure that the main engine-runs under the best situation. And it compares the running parameters after optimization with the parameters before and after cutting, which shows that oil consumption, combustion temperature and exhaust gas temperature all decrease, but working pressure, power and torque all increase. And the optimization after cutting can improve the economical efficiency, power performance and exhaust behavior.The achievement which is acquired by this paper has profound significance for reducing fuel cost and greenhouse emission from shipping.