Resistance And Floating Condition Numerical Simulation Of A Ballast-free Ship Type

To control effectively the pollution problem of ballast water,in 2004,IMO issued International Convention for the Control And Management of Ships' Ballast Water and Sediments,aroused the research upsurge of ballast water treatment system in the industry.However,due to the difference of different vessel types,no unified standard can be achieved,it is difficult to meet the different requirements of all types of vessel.Thus,academic circle presented the "ballast-free ship" theory.The design of new ship model needs to consider two aspects including statics and dynamics,and analyze six characteristics of ships together.At present,the study of ship performance has two major methods:experiment and calculation.In the experiment methods,real ship experiment has the high cost and long period,model experiment has the problem of scaling effect.In the calculation methods,the accuracy of the empirical formula and the mathematical equations of motion still need to be improved.However,under the background of high level computer technology,compared with the above methods,the numerical calculation of CFD has the lower cost,shorter period and higher precision,and has the great application value for the study of ship performance.Based on foreign researches,firstly,in this paper,the water flow box in American though flow system is transformed into the three vertical and horizontal connected pipeline,Japanese V-Shape hull is transformed into the "upper U,under V" hull.After merging with each other,this paper introduces a new ballast-free scheme and applies to Panama ship model,and modifies the model lines by using CAD software.Meanwhile,on the basis of empirical formula,new ship form parameters are calculated,results turn out that the design scheme meets the related requirements of practice and is feasible.Moreover,this paper selects the standardized ship type-Series 60 ship model as the object of verification to explore the new ship's rapidity and floatability.Firstly,based on the CFD method,the numerical simulation of new ship's resistance and floating condition are carried out by solving the RANS equation.In the calculation process,using the finite volume method and hybrid grid technology based on the SIMPLE scheme,the RNG ?-? model is chose as the turbulence model.Then,the results of the Series 60 ship model's resistance coefficients are compared with past researcher's experiment results,and the results are in good agreement,proving the accuracy of the numerical analysis method.The resistance and floating condition numerical calculation results of the Series 60 ship model and new ship model are compared,analyzing the improvement of ship's rapidity and effectiveness of floating condition adjustment,and analyzing that the changes in the structure weaken the influence of the fluid domain around hull to its navigation state.In this paper,the ship form parameters,resistance and floating condition of ballast-free new ship is calculated,under the premise of high computational accuracy,the results basically meet the relevant design requirements,and can provide a reference idea for the design of ballast-free ship.