Experimental and theoretical investigation of a tilting pad journal bearing for application in high-speed turbine aero engines

High-speed turbine aero engines should be able to perform reliably and work in different flight regimes. Choosing the type of bearing and its design to ensure the performance of the rotating part of these engines in all working conditions is of particular importance Conventional rolling and fluid film bearings are not able to adjust their dynamic behavior in response to changes in the working conditions of the system. Tilting pad journal bearing (TPJB) can eliminate axial vibrations by compensating for misalignment, adapting to speed changes and active damping, and cause stability of operation and reduction of oil film instability. In the design of this type of bearings, the loading method, preload, length-to-diameter ratio, vertical force and starting torque, hardness and equivalent damping, and increase in oil temperature are important. In this research, a bearing sample for a shaft with a specific diameter was designed and manufactured and tested according to the requirements. In order to evaluate, tests are performed at different speeds and the results of the tests are expressed. The results show that while the Shaft moves smoothly and without vibration up to 13000 rpm, the lubrication is in the hydrodynamic range. With the initial parameters including Summerfield 13.6, temperature 23.5oC, 3570 rpm and viscosity 0.034 Pa.s, with the increase in temperature to a ratio of 1.4, while reducing the viscosity ratio to 0.62 and reducing the number bearing characteristics to 0.67, Summerfield number is also reduced. The extracted diagrams show the correct design of the intended bearing.