Lubrication characteristics can greatly affect the service performances of ball bearings. To further clarify the variation law of oil-air distribution in bearing cavity, a new simulation method combining the dynamic and computational fluid dynamics (CFD) models is presented. The relative motion relationships between the bearing components caused by the cage clearance are obtained by the dynamic model. The coupling model uses the multi-reference frame (MRF) method and local remeshing approach (LRA) to describe the motion of each bearing component. The oil-air two-phase (OATP) flow is described though the volume of fluid (VOF) numerical model. Note that the lubricating oil content in the bearing cavity decreases significantly with the increment of rotation speed. There is a sudden change of pressure at the contact zone between the ball and inner raceway. The relative motion of ball caused by the cage clearance has some effect on the local lubrication; however, it has little effect on the overall lubrication characteristics.
The turbine rotor system (TRS) is one important part of an underwater vehicle (UV). Its vibration and noise characteristics can greatly affect the performance and service life of the UV. To study the influence of radial clearance of supporting bearings on the vibrations of the whole TRS of the UV, a flexible dynamic model of the TRS is established by using the finite element and multi-body methods. Vibrations of the TRS from the rigid and flexible dynamic models under different bearing clearance conditions are analyzed. Note that the TRS with the flexible body model can obtain more accurate vibrations than the rigid one. The maximum vibration amplitude increases with the increment of bearing clearance. The bearing clearance of 5 micrometers to 20 micrometers is more reasonable for controlling the system vibration. The smaller clearance of supporting bearings of the TRS can cause more stable vibration responses. This paper can provide additional guidance for the accurate simulation analysis method of the TRSs of the UVs.
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