Study On The Effect Of Route Optimization On Energy Saving Of Wing-assisted Ships

Aimed to the global important demand of energy-saving and emission reduction,and urgent need of transoceanic crossings to cut down fuel costs,this thesis,focusing on route optimization for wing-assisted ships,can provide theoretical basis and technical support in the hope that the ocean wind resources can be utilized effectively.According to the monthly mean grib data of a 20-year record from ECMWF,the distribution characteristics of ocean wind speeds and direction are analyzed,and it is found that the wind field in summer and winter keep stable for a long time,so that the ocean wind resources are available for wing-assisted ships.Based on the above conclusion,this thesis proposes a new idea that the wing-assisted ships can make maximum use of ocean wind as auxiliary thrust and finally achieve the energy-saving and shipping efficiency improvement through taking some suitable deviations on their original routes in the condition of global optimum,which is also called ship route optimization.Secondly,through the analysis of wing-assisted ship's force,the MMG model for the target ship is builded.According to result of wind tunnel experiment on the target sail,Then,the wing model is programmed,then the best angle of attack of the sail under the different relative angle is analysed So the relationship between maximum thrust coefficient and the relative angle is got.By comparison the data of target ship trial experiment and the simulation data of no wind field,verified the accuracy of the model under the condition of no using of wind sail,the basis for route optimization calculation can be provided.In the condition of fixed shipping date,reduce the main engine power as it does,a wing-assisted ship can keep her speed by the using of the auxiliary power that provided by ocean wind resource,and thus reduce her fuel consumption calculation model and evaluation criteria for route optimization are modeled in the condition of fixed ship speed,and the route optimization are modeled in the condition of fixed ship speed,and the route optimization model for "minimum energy consumption " is built finally.At last,by considering the characteristics and computation scales,the model can be solved on the basis of dynamic programming.A 30,0000 DWT wing-assisted VLCC is taken as the experimental ship by which the optimization models and their algorithm are simulated and vertified.The simulations indicate that the fuel consumption can be reduced by 4.41%,and the navigation time increases 4.17h and the distance increases 4.46%.In conclusion,the research result in this study can be applied to optimize the of new ships named wing-assisted ships,and to guide the modern ships to use the ocean wind rationally as an alternative auxiliary energy.Besides,it also has a significance of guidance for the solving energy saving optimization problem of the ship.