Pad shimmy characteristics of tilting pad bearing in heavy duty gas turbine

Here, taking a 4-pad tilting pad bearing as the study object, the dynamic analysis model of pad shimmy characteristics of tilting pad bearing was established. Based on the variable separation method, the approximate analytical expression for oil film pressure of tilting pad was derived. The dynamic responses of pad were calculated using Euler method. The correctness of the analysis model and analytical calculation method was verified with tests, The influence of preload factor on pad shimmy characteristics was studied, and the swing angle response of pad under step excitation was analyzed in detail. The results showed that the dynamic bearing capacity of tilting pad bearing in heavy duty gas turbine can be improved by applying a certain preload factor; there is a special preload factor within the range of 0.5-0.8 to make No.1, No.3 and No.4 pads have swing angle maximum values; increasing preload factor can make swing amplitude of each pad decrease by more than 90%; the swing frequency of each pad under different preload factors is rotating frequency, but the upper pad can have obvious frequency doubling when the preload factor is smaller; the study results can provide a reference for diagnosis and treatment of tilting pad bearing instability fault caused by pad shimmy. © 2021, Editorial Office of Journal of Vibration and Shock. All right reserved.