Hydrodynamic Ferformance Analysis Of New Energy-saving Duct In Front Of Propeller

With the increasing speed of global economic development,ship has become an indispensable part of international trade,and the increasingly serious impact of energy shortage,the application of energy saving appendages of ships is imperative.The ship quant front energy-saving duct is one of the common energy-saving appendages,which is installed on the stern quant hub and has direct influence on quant.The quant of conventional ship type has high convection zone at the small radius of the quant surface and above the quant surface.Therefore,it is of great engineering value to add energy saving duct between hull and quant to improve the flow field before quant.In this thesis,the resistance performance prediction of the duct and the hydrodynamic performance calculation of the ship-propeller-duct coupling are carried out around the new propeller energy-saving duct,and the accompanying flow at the stern flow field and the paddle surface is analyzed to further optimize the new propeller front Parameters of energy-saving ducts.The main research contents are as follows:(1)The analysis of resistance performance of duct was performed based on the method of numerical simulation for new energy-saving duct.The resistance performance of KCS ship model with a new energy-saving duct was predicted by RANS method.The resistance of the catheter at different speeds was compared,and the law of increasing resistance of the new energy-saving duct was investigated.The working principle of the energy-saving duct was analyzed according to the distribution of the stern flow field and the associated flow at the surface of propeller after the duct was installed.(2)The hydrodynamic performance of the new energy-saving duct and the numerical prediction of the stern flow companion were performed by the self-propelled numerical simulation.The self-propelled calculation of KCS model and KP505 propeller was performed by slippage grid technique.The accuracy of the self-propelled calculation method was verified by comparing the calculation results with the tested values.The self-propelled calculation was performed again after installing the new energy-saving duct on propeller coupling model,and the results of the self-propelled calculation(open water efficiency of propeller,hull efficiency,propulsion efficiency,etc.)were compared,to evaluate the energy-saving efficiency of the duct.The changes of the velocity at the rear wake field and the surface of propeller were analyzed,to further reveal the influence of the new energy-saving duct on the hydrodynamic performance of the paddle.(3)The parametric simulation analysis of the hydrodynamic performance was completed by changing the different influence parameters of the new energy-saving duct.The individual parameter of the new energy-saving duct was changed(duct mounting position,guide plate radius,stator angle of attack),to get the self-propelled points under each working condition.The specific law of the influence of the change of duct parameters on the hydrodynamic performance of the propeller was obtained by comparing the results of calculation(thrust of propeller,torque,efficiency of back propeller,etc.)at the self-propelled point of each working condition.Based on this,a new energy-saving duct with better energy-saving effect was designed.