The Numerical Analysis Of Propeller-rudder-ball-fin System’s Hydrodynamic Performance

Since the financial crisis, the price was soaring and the resource was decreasing, thetopic about energy-saving was paid more attention. Ship as an important tool in internationaltrade, and its energy-saving problem had been drawing wide attention. This paper wasdiscussing the thrust system of ship, propeller-rudder-ball-fin system’s energy-saving effectanalysis, in recent years because of such energy-saving devices were easier to produce, theprice were lower and energy-saving effect were better which were received much attention.Foretime people used potential flow method to study these problems, due to the rapiddevelopment of computer technique and CFD technique came into being, in this paper usingCFD method for rudder devices rudder ball and fins’ theoretical studying.First, the paper used computational fluid dynamics software FLUENT to study propelleropen water performance which was in the viscous flow, the propeller’s large computationalregion generated structure grid and unstructured grid, conducting the values of these two typegrids and then comparing the calculating values with the experimental values, finding it meetthe engineering requirement. So it made sure that CFD method was viable for calculatingpropeller open water performance and the structure grid and unstructured grid had little effecton the results, both could be applied.Second, actually propeller and rudder worked together, experimentation and surfacepanel method showed that the rudder would have an impact on propeller. Next the paper usedCFD technique to calculate the efficiency of propeller-rudder and found that the rudder canincrease the efficiency of propeller and had favorable interference with the propeller. Then thesame theory was used to calculate the hydrodynamic of propeller-rudder-ball system andpropeller-rudder-ball-fin system, in order to analyze the energy-saving effects of theappendage.Finally, this paper studied the different sizes of the ball and the different installationpositions of the fins that made a certain effect on propeller efficiency, and calculating the ballsizes and the fins’ positions which made the energy-saving effect best, then comparing theefficiency of propeller-rudder-fin system with propeller-rudder-ball system, picking out thedevice of best energy-saving effect. The reason to study so many situations, one was to provethe validity of CFD method to calculate propeller open water hydrodynamic performance; the other was to find out the best way to make the energy-saving best.