Research On Ship Optimization And Appendage Based On CFD

In today’s energy crisis situation,ship owners are keen to reduce the resistance of the vessel hull and improve the efficiency of ship propulsion.The assessment of the performance of ship resistance is an important basis for optimization of ship.Ship resistance prediction method has been the main ship engineering research.Recent the studies of ship energy-saving appendage is very hot,for fat large ships install energy-saving appendage is a simple and effective energy-saving measures.The main research methods are theoretical method,experimental method and numerical simulation.With the rapid development of computer technology,CFD method based on fluid mechanics has gradually become an important method.Compared with traditional methods,CFD method is more flexible and economical.In this paper,the CFD calculation tool was used to calculate the total resistance of the bare hull of a target medium-speed ship,and the results were compared with those of the pool test.Meanwhile,the appendages such as bilge keel,wave plate and caudal fin were analyzed.The range of resistance variation caused by various appendages under different parameters is obtained and the main causes and components of resistance variation are analyzed.Then the simulation analysis of the propeller’s open water performance and self-navigation factor is carried out,and the CFD prediction of the self-navigation factor is realized.The results show that: the total drag near the design speed increases by about 5% after the bilge keel is installed on the target ship.Based on the analysis of bilge keel,it is concluded that the setting of caudal fin will increase the total resistance of the hull,and the resistance of the design speed will increase by about6%.The precision error of resistance prediction of the fully attached model is controlled at about 5%.The open water test of the propeller is simulated by the method of overflow with constant speed.Kt error is around 5%,Kq error is around 3%,and eta error is around 5%;The prediction error of self-propelled point speed,torque and thrust parameters can be controlled within 3% basically,which has met the requirements of engineering application.This paper can be concluded that in finding the right conditions,the calculation methods of CFD using CFD method for ship form resistance prediction research work,can greatly reduce the workload ship form optimization,the methods in this article use similar medium-speed ships reducing ship resistance and improve the efficiency of ship propulsion also to have certain reference significance.It paves the way for further research to improve the propulsion performance,optimize the design of appendages and improve the ship’s shape.