Changing the performance of the fixed pad thrust bearing during the centrifugal compressor surge

The article presents numerical studies of the effect of the displacement of the rotor collar during the centrifugal compressor surge within the axial clearance on the local, integral and dynamic characteristics of a fixed pad thrust bearing. When setting a direct dynamic problem using the Sm2pх3Tхτ program, an analysis of changes in load-bearing capacity, damping, formation of a vacuum in the bearing lubricant film, temperature mode of operation and changes in power losses was carried out. The Sm2pх3Tх? program is based on the numerical implementation of a periodic thermoelastohydrodynamic mathematical model, which includes the calculation of thermal, hydrodynamic and deformation effects in the lubricant film and boundary layer of a thrust bearing. A significant effect on the considered characteristics of the thrust bearing of the collar displacement velocity relative to the plane of the pads under the action of an external disturbing axial force of the compressor is noted. In comparison with the harmonic displacement of the collar, more significant dynamic loads on the bearing pads occur during surge. At the same time, the hydrodynamic pressure field in the lubricant film changes significantly depending on the coordinates and time. Prolonged exposure to variable pressure and temperature can adversely affect the working surface of the bearing pads due to the fatigue strength of the babbit. The combination of high temperature and hydrodynamic pressure at certain points can lead to exceeding the yield strength and/or endurance, the beginning of the destruction of the babbit layer and the failure of the fluid film bearing. The most probable zone of the beginning of the destruction of the working surface of the pad near the trailing edge has been determined. The developed Sm2pх3Tх? program allows you to simulate the described cyclic processes of various forms of collar movement and determine the probable zone of the beginning of destruction.
EDN: QXFYEJ, https://elibrary/qxfyej

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