The Study On Wind-assisted Technology Of Ship

According to the estimate of the energy specialist,Fuel consumed by shipping takes up 5%of the total fuel consumption all over the world.With the deterioration of energy crisis and environment issue,the energy conservation and environmental protection are increasingly focused on;on the other hand,although it is very low today,the price of crude oil will continue to rise because of the oil shortage.And energy conservation is also very important at the economic benefits for ship companies.Therefore,scientists and engineers continue to search for new solutions, some to improve the existing machinery,and some turn to the new energy or the wisdom of their predecessors for help.This paper is about to turn to the wind energy: kite-like sail,which is ancient,but is innovative method.Firstly,the sail of aerodynamic characteristic is researched through numerical simulation by changing the camber and attack angle,then obtain curves showing relationships between the lift coefficient,the drag coefficient and the camber and relationships between the lift coefficient,the drag coefficient and attack angle. Secondly,the method of calculation for sail energy-saving effect is put forward.The sequence of this calculation method is:calculating the lift coefficient and drag coefficient induced by sail and some other components of sail;establishing the sail operation mathematical model that transforms the relationships among relative velocities and angles to a certain mathematical relationships;Based on the assumption that the resultant force on the kite is parallel to the tow line,this paper obtains the kite relative velocity,and then with the velocity,calculates the lift and drag forces of the kite;analyzes off-design situations of propeller and main engine and obtains the power of main engine;obtains the amount of the fuel saved by kite according to the main engine characteristics curves.Finally,the propulsion characteristics of the sail,the resistance characteristics of the hull,the propulsion characteristics of the propeller and the propulsion characteristics and speed characteristics of the main engine are discussed respectively. The ship's energy and force balance are changed after the installation of sail,so this paper also discusses the balance of the ship energy transfer and force balance.The two parts mentioned above prepare for the analysis and calculations of influence that two different operation modes have on the main engine respectively,the two operation modes are constant speed mode and constant power mode.Through the calculation of a specific case,this paper finds the way two different operation modes influence the main engine and propeller,and then puts forward the methods to solve the problems occurring at two modes.