Research On Ship Optimization And Energy-saving 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.This article, based on a fat large ship, is aimed at reducing hull resistance and improve paddle propulsion efficiency.So the article is a feasibility study on ship hull optimization and additional Energy-Saving appendage. In the article, I use CFD applications to predict the hull resistance and the hull viscous flow field. By comparing the result and choosing a favorable ship optimization program, the result of model test proves the reliability of numerical simulation of CFD. And the result also provides a reference for that type of ship designing and construction.In this paper, I use CATIA software to establish the hull geometry and mesh the blocks with ICEM software.Complex large ships should use multi-block structured grid. The boundary layer near the hull needs to be encrypted so that to ensure a smooth transition of the grid and improve accuracy.Firstly,I use CFD to calculate the ship resistance on the design draft of 6.9m. The calculation results with the same state of ship model test results concluded after comparing shows that, with SST k-? turbulence model to calculate the original design of the ship's hull resistance is feasible.Secondly,this paper analyzes the resistance component and drag reduction programs,optimizes the bulbous bow and hull profiles. And repeatedly I use CFD to calculate various optimization programs.The conclusion is the choice of the original bulb shape while optimizing the fore body line and after body line.The drag reduction rate is more than 4%,which shows that the effect of drag reduction is more obvious with the speed increasing. And the testing modifications of ship model certify CFD calculation error is within 2%.This paper then analyzes the characteristics of the ship.In order to achieve the purpose of improving the efficiency, I decide to add pre-compensated flow conduit with the modification ship.After CFD numerical calculation,we clearly see the success of the improvement which the pre-catheter brings to the hull wake field from the propeller plane at the wake distribution.We can clearly see the influence of that the pre-catheter weakened bilge vortex from the end of the flow chart. Finally, self-propelled ship model hull resistance tests show that additional pre-catheter modification of the ship reduce the ship resistance by 2% to 6%.Model ship propulsion efficiency is improved by more than 10%.Contents of this paper can come into a conclusion that, in the right CFD calculation conditions, using CFD calculation for ship optimization and ship Energy-saving appendage can greatly reduce the workload. The methods used in this paper have some reference,especially for similar reduction of fat large vessels ship resistance and improvement of the efficiency on ship propulsion.