The Lubrication Performance Research Of Water-lubricated Bearing Based On Fluid-structure Interaction

Water lubricated rubber bearing is widely used in mechanical equipments, such asship, water turbine and water pump due to its good lubrication performance. However,the lubricating mechanism is complex compared to traditional oil lubrication metalsliding bearing, since the water lubricated rubber bearing has multi-surface andmulti-groove geometric structure, as well as low rubber lining stiffness and lubricatingmedium viscosity. This paper investigates lubricating characteristics of water lubricatedrubber bearings as a function of working conditions, geometric structure and lubricationmedium with fluid-structure interaction technique.First of all, the flow field was assumed to be turbulent flow according to theinstallation clearance, rotate speed and geometric structure of bearing. Themathematical model for eight groove water lubrication rubber metal bearing was thenconducted by using the dynamic pressure lubrication theory and the fluid-structureinteraction theory. The inside flow fields during the bearing movement was analyzedusing ANSYS Fluent. The reliability of the fluid-structure coupling numerical methodwas validated by comparing the water film pressure distribution from the simulationresults and the experimental tests.Next, the effect of working condition, bearing geometry and lubricating mediumwas investigated. The numerical results of fluid-structure coupling show that highrotation speed and eccentricity play a positive role to form the hydrodynamic pressure.By reducing the groove radius, both the bearing capacity and the effective stressdistribution between the rubber lining and the copper bonding interface can beimproved, and the friction coefficient of bearing is reduced as well. Smaller transitionalfillet radius can increase the effective length of wedge of convergence, and hence theperformance of lubrication is enhanced. The simulation results also indicate that it’sbetter to use bearing with circular arc surface than that with flat surface to get optimalbearing capacity. Common lubricating medium, including fresh water, salt water, andsand water, influences the water film pressure. When using fresh water as lubricatemedium, the pressure is lower than using salt water, while the pressure is highest ifusing sand water to lubricate. The pressure will be further increased if the lubricatingmedium has higher salt concentration，contrary to sand concentration. The experiment was conducted to test friction coefficient of water lubrication rubber under differentbearing geometry and lubricating medium, the test results are consistent with thenumerical simulation.This research is funded by the State Natural Sciences Foundation General Projects:“Research of the vibration and noise mechanism and reliability on the large-size waterlubricated rubber alloy bearing”(Number:50775230). The paper will provide a newreference for the study of lubrication mechanism and research methods...