Simulation Calculation Of Oil Film Force And Stress Of Ship Propulsion Shafting Stern Bearing

As one of the main components supporting large rotating machinery,the performance of sliding bearing is directly related to the work schedule,life,reliability and many other economic and technical indicators of the whole operating system.So the sliding bearing plays a very important role in rotor machinery.This paper takes the propulsion shafting stern bearing of a 39000 DWT series bulk carrier as the research object.The stern bearing is a typical sliding bearing,which can protect the stable operation and power loss of the shafting.However,due to the influence of poor lubrication,lubricating oil loss,shafting failure and other factors,the tail bearing can not work normally.Therefore,the research on the lubrication performance and structural characteristics of the propulsion shafting tail bearing in this paper has practical research background and engineering significance.Based on the summary of a large number of research literature on sliding bearing,this paper determines the research ideas of this paper,mainly in two aspects: first,establish the boundary conditions of oil film rupture and re-formation and the air cavity model,and analyze the steady flow field distribution and lubrication performance of the oil film of the tail bearing based on CFD calculation method;In the other part,based on the analysis of oil film pressure,the results are coupled to the tail bearing to study its influence on the stress and deformation of the tail bearing.This paper mainly introduces the working mechanism of fluid lubrication,the basic governing equation of computational fluid mechanics,and the governing equation of fluid-solid coupling,etc.Through simulation calculation,the following contents are emphatically studied:Firstly,in this paper,the basic computational fluid dynamics governing equation for simulating the oil film flow field of tail bearing is established,the basic assumptions and boundary conditions for calculating the oil film flow field of tail bearing are determined,and reasonable calculation parameters of the simulation model are obtained.Through comparison,it is found that the cavitation model is more in line with the actual distribution of the oil film flow field.Secondly,the established 3d model of oil film was meshed,mesh independence was verified to determine the number of meshes,and the pressure field and temperature field of oil film were simulated and calculated in Fluent.The results showed that the oil film pressure reached its peak in the wedge convergence area and gradually decreased in the divergence area.The oil film temperature is the lowest at the inlet and the overall temperature distribution increases from the middle to both sides of the bearing.Thirdly,the influences of different oil inlet modes,different rotation speeds,different oil inlet pressures,and different oil inlet temperatures on oil film pressure distribution and oil film bearing capacity were studied to provide certain reference for the change of flow field in different lubrication conditions of shaft stern bearing.Fourthly,the results of oil film simulation were coupled with the tail bearing and the cloud diagram distribution and variation of the stress and displacement of the tail bearing under different rotational speeds were obtained by ANSYS Workbench.