Hydrodynamic Performance Prediction Of Contra-rotating Propeller Under Different Working Conditions And The Rescearch Of Non Synchronous Counter-rotating Propeller

In recent years,with the increasing of energy consumption and the improvement of environmental protection consciousness,the enthusiasm of scientific research workers of the various efficient propulsion unit research also gradually rose,as a result the contra-rotating propeller has attracted more and more attention of researchers by dint of its excellent properties.This article study on the hydrodynamic performance of contra-rotating propellers by by using CFD simulation,firstly Using the sliding mesh function of Star-CCM+ to simulate the open water hydrodynamic performance of contra-rotating propellers,which verified the precision of Star-CCM + by comparing its results with experimental data.In order to fully understand the advantages of the contra rotating propeller to other forms of the propeller,this article juxtapose the after propeller and the forward propeller to research how the propeller pitch influence the propeller performance of propellers in opposite rotation direction.And then this article verified the advantage of contra-rotating propellers by comparing the results.When the ship navigate in shallow water,the contra-rotating propeller will be affected by water bottom.Besides that,the contra-rotating propeller will be affected by free surface with With the application of the rotating propeller in the field of inland river ship,which cause the the contra-rotating propeller in a small dip deep working situation.So,this article research how the hydrodynamic performance of contra-rotating propeller influenced by the bottom and analyse the wake of propeller firstly.In consideration of the existence of gas-liquid flow,the correct simulation of free surface is very important to simulate the viscous flow around accurately in the study of influence of the free surface to the contra-rotating propeller.This article use the method of VOF which can effectively deal with complex geometry and the effects of wave breaking in order to simulate the free surface accurately.And The results sugges that the method can forecast the hydrodynamic performance ofthe contra-rotating propeller under the influence of the free surface correctly.With the the development of the shipbuilding technology,the the contra-rotating propeller are applied in varied forms.For example,the demand of space must be considered when the contra-rotating propeller is applied to CRP.So,the spacing between the after propeller and the forward propeller is different under different circumstances.In view of this,this article research the hydrodynamic performance of contra-rotating propeller under different circumstances.The speed of the after propeller and the forward propeller of traditional contra-rotating propeller are equal,and the research of Non synchronous contra-rotating propeller is rare.This article change the speed of the after propeller and the forward propeller which make them form Non synchronous contra-rotating propeller.On that basis,this article research it`s hydrodynamic performance preliminarily and some beneficial attempts andapproaches were tried.