Research On Fluid-structure Interaction Simulation And Structure Optimization Of Water-lubricated Stern Tube Bearings

Water lubricated stern tube bearing is an important component of marine propulsion. Compared with ordinary oil lubricated bearings, the water lubricated stern tube bearings is basically non-pollution, safe, low cost, less auxiliary equipments, easy to use and maintenance. Carrying out the research of water-lubricated stern bearing and promoting its application has important theoretical and engineering application significance for the development of "green shipping".In this paper, the ship of water lubricated stern tube rubber bearings is taken as the study object and the finite element fluid-structure interaction and the contact characteristics of theoretical study is carried out to discuss the influencing law of the water lubricated rubber bearing under the different materials, working parameters and the structural parameters. The main work and research conclusions are as follows.1. ADINA software is applied to establish a single strip FSI model of water lubricated tail rubber bearing. Through the simulation, the water film approximately parallel zone, the second peak pressure, necking and reflux phenomenon, and other lubrication characteristics are analyzed and the water sac formation mechanism is described.2. The influencing law of fluid-solid coupling lubrication properties of different materials, working conditions and structural parameters is studied. The results show that:as the increasing of rubber hardness, the benefits of elastic deformations are disappeared gradually and when the rubber hardness reaches 75 HA, the water film bearing capacity reaches the maximum; rotating speed is a major factor for elastohydrodynamic lubrication water film thickness and pressure distribution; eccentricity ratio could simulate loading of stern bearing indirectly; concave rubber strip which has panels of larger radius should be adopted and the bigger the design pressure is, the larger the panel radius is and even could be flat; the rubber thickness has a optimal value between 3～10 mm, which could make the rubber has better comprehensive properties and when the rubber is thick enough, the joint surfaces form has not big influence on the strip character; in order to form rational water film wedge angles and make full use of the length of strip, the number of strips should combined with the panel radius.3. The influencing law of structure and contact characteristic of rubber strip is discussed in this article and the formation of water film wedge angle and water sac is analyzed from the point of strip deformation. The results indicates that:concave strip of larger panel radius has better comprehensive properties; joint surfaces form of rubber and basement material has less influence to the deformation of strips; thick rubber could improve the stress state but against lubrication; when the journal's radius is 199.2mm and the number of strips is 20; it has better capacity and lubricant character; the rubber basement cannot be too soft, if not, the water inlet will be too small and the water sac will be long and that leads to worse lubricating.