Study On The Influence Of Propeller Hydrodynamics On Propulsion Shafting Under Steering Conditions

With the improvement of the high maneuverability requirements of modern ships,the actual bearing bearing force and the bearing load of the propeller differ greatly from the design conditions.During the actual navigation of the ship,the drastic fluctuation of the hydrodynamics of the propeller under different working conditions is one of the important reasons for the high temperature wear caused by the overload of the bearing.In order to solve the problem of high temperature wear of ship and bearing,this paper takes a 64000 DWT bulk carrier as the research object,applies the Realizable turbulence model based on CFD method,and considers the ship-paddlerudder system by establishing the three-dimensional solid model of hull,propeller and rudder.The hydrodynamic changes of propellers under direct flight conditions and different rudder angle rudder conditions under interaction conditions,and further analysis of the effects of propeller hydrodynamic changes on ship bearing load,bearing oil film pressure distribution and shafting state.Firstly,according to the physical characteristics of the research object,the fluid calculation domain of the single propeller and the rudder propeller is divided,and based on the Realizable turbulence model in FLUENT software,the numerical simulation and calculation of the propeller hydrodynamics are carried out by using the steady analysis method,and the direct flight conditions are compared.The velocity field,pressure field and propeller thrust coefficient curve of the single propeller and the rudder propeller are analyzed under the condition,and the influence of the existence of the rudder on the propeller load and propulsion characteristics is analyzed.The results show that the existence of the rudder under the direct flight conditions has a certain positive impact on the hydrodynamic performance of the propeller.Secondly,in order to study the hydrodynamic variation of the propeller under different working conditions under the interaction conditions of the ship's rudder system,a complete ship rudder model is established based on the multiple reference system model,and the propeller rotation domain and the static water near the hull are divided and passed through the stern.Field simulation,comparing the changes of propeller speed field,pressure field and thrust coefficient under direct flight conditions and rudder conditions,studying different advance speed coefficients,different rudder angles for propeller thrust,horizontal lateral force and lateral bending moment,and vertical direction The effect of force and vertical bending moment.The results show that with the increase of the advancement coefficient,the thrust of the propeller increases,but the thrust coefficient decreases gradually.With the increase of the rudder angle,the thrust coefficient does not change significantly,but the rudder angle affects the horizontal and lateral bending moments of the propeller.The effects of vertical force and vertical bending moment are very significant,and the direction of vertical force and moment has even changed.Finally,based on the theory of shafting dynamic alignment and bearing oil film calculation,according to the analysis results of hydrodynamic changes of propeller under the rudder system of the ship,Ansys software is used to bring the propeller hydrodynamics under different working conditions as input parameters into the calibration equation.The calculation is performed in the school,and the calculation results of the finite element method and the traditional transfer matrix method are compared to verify the correctness of the model and the algorithm.The calculation results of the back force and the combined angle of the dynamic bearing are used as the input parameters.The Reynolds equation is used to solve the bearing oil film thickness and pressure distribution,and the calculation results under direct and rudder conditions are analyzed and compared.The results show that the propeller hydrodynamics have different effects on the bearing load distribution and oil film lubrication under different working conditions.