Study On The Influence Of The Added Resistance On Marine Main Engine Power

With the global energy crisis and increasingly deterioration of air pollution problems,energy-saving and emission-reduction has become the focus of the shipping industry.In this paper,the research on the influence of ship resistance on the power of the main engine is one of the key points of the energy efficiency optimization project and the basic research on the follow-up research on course and speed optimization of the project,which is of great significance.This paper selected 300000 tons VLOC target ship to establish the three-dimensional model and analyzed the effect of different load conditions and sea conditions on the added resistance of ships and sea-keeping through using analysis method of controlling variable.Then we can find the appropriate algorithm to calculate the corresponding main engine power,and analyze the influence of the added resistance on the main engine power.Firstly,this paper compared different calculation methods and finally chose Maxsurf software as a simulation and analysis tool through consulting relevant literature on added resistance in waves and sea-keeping.Based on the analysis of wind and wave data of the South China Sea-Malacca typical course by European weather forecast center in the past one years,according to the parameters of the target ship,the three-dimensional model of the ship was established and compared with real ship data to verify model accuracy.Secondly,an algorithm for finding the appropriate target ship motion amplitude response to operator,according to the different navigation states of ocean going vessel.The frequency response function of the regular wave was calculated,and the three factors(heave,pitch,roll)which affected the safety of the ship in random waves were analyzed.Analysis and calculation of four factors of significant wave height,wave period,wave angle and load conditions effects on added resistance in waves and sea-keeping.To find a suitable method to calculate the main engine power,the propeller thrust-efficiency curve was used to determine the propeller efficiency,so as to calculate the main engine power,calculate and analyze the effect of added resistance on main engine power.Finally,this paper comprehensive analyzed the calculation results and arrived at a conclusion.The results showed that when wave angles was in the range of 90° to 180°,with the increase of wave angles,the curve of added resistance in waves showed a decreasing trend,while slightly increasing when head sea arrived;under the same conditions,the added resistance in waves was smaller corresponds to the faster speed,while much smaller under full load condition than under ballast load condition,which was quite considerable.When the significant wave height increased to 2m,the amplitude of the main engine power which increased with the increase of the significant wave height increased,it is suggested that the speed should be appropriately reduced to reduce the main engine load when the significant wave height was higher than 2m.When the sea condition was bad,the wave height and wave angle were unfavorable,it is recommended to maintain a head sea,full load and low speed navigation to reduce the main engine load and increase the operational economy.