Study On Energy Optimization And Minimal Engine Power Of Double-sail Boat

Energy saving and emission reduction is the main characteristics and trend of development of the modern and the future of the ship,and the EEDI(the energy efficiency design index)is an important indicator to measure the efficiency level of the ship.Sail assist ship has great potential in energy saving and emission reduction.The sail assist device can improve the energy efficiency and reduce the power of the host.So how to design the sail form,optimize the layout of the sail,choose the right route and improve the energy efficiency is the focus of this paper.In May 2013,in the sixty-fifth session of the MEPC,Temporary guide of minimum mainframe power for maintenance maneuverability of ships under adverse sea conditions(The following is referred to as the "provisional guidelines")was adopted by the Organizing Committee as a resolution of MEPC.232(65).According to the regulations,the interim guidelines will be applied to the first stage of the implementation of the EEDI rules(PhaseO),and it is effective for bulk carriers,tankers and dual-purpose ships,so we should consider the heading stability of sail assist ship in harsh seas.This paper is based on the principles of safety,reliability,engineering,economy and so on,so we choose the Panama bulk carrier with 76000 tons of load.In combination with the requirements of the sail structure,height,width and shape,the fixed airfoil NACA0016 is chosen as the sail of the target ship.The paper studies energy efficiency optimization in the aspects of two sail spacing,wind direction,two sails rotation angle,and determines that when the space of two sail of is the maximum 5L(125.4m),the wind direction is 40 degrees and the bow at the sails fixing a rotation angle is 30 degrees,the stern sail rotation angle is 60 degrees,the maximum thrust of the sails is 110000 N,and the percentage of EEDI decreases to the maximum value of 13%.This paper selects the Shanghai-Panama route as the target route,which will be divided into 8 segments.We refer to the average wind direction distribution and specific routes in the North Pacific in January to determine each leg of the distance,the true wind speed and relative wind speed.By changing the angle of rotation of two sails to determine the fuel consumption of each segment within two sails optimal rotation angle and target ship to reduce fuel consumption,we finally get that the total leg installation of sail device is reduced to 29135.43kg.According to "provisional guidelines",after verification,The requirement of a sailing ship that does not meet the minimum power of the mainframe at the speed of service.The ship meets the minimum engine power requirements with minimal speed sailing voyage Assuming that the rated power of the real ship is the minimum host power,the resulting EEDI value is 3.149,which is less than the EEDI value of the third stage of the reduction factor 3.162.It indicates that the EEDI value considering the minimum main power of the ship satisfies the reduction requirement of the third stage in the EEDI specification.