Dynamic performance and wear of ceramic aerodynamic tilting-pad journal bearings: Tested and simulated under excessive vibrations

Ceramic aerodynamic tilting-pad journal bearings are emerging as a crucial component in hydrogen-electric mobility, specifically within electric compressors that deliver compressed air to hydrogen fuel cells. These bearings provide an environmentally friendly solution by eliminating the need for oil lubrication, thus preventing contamination of the fuel cells. This study focuses on the wear performance of these bearings under extreme conditions, operated near critical bending speed with elevated vibrations surpassing assembly clearance levels. To assess performance, a custom high-speed test rig was developed, designed without coupling to ensure precise measurements and to prevent the transfer of vibrations from the electric drive to the bearing system. Detailed vibration measurements were conducted under extreme conditions across various rotational speeds, reaching up to 70000 rpm. Alongside this, a dynamic computational model of the aerodynamic bearing was created, incorporating an analysis of rotor vibrations. Experimental results were systematically compared with simulation data to validate the model's accuracy. Key to this study is the wear assessment of the bearing pads under these demanding conditions. The findings reveal that the proposed bearings exhibit reliable performance even in highly demanding scenarios, demonstrating their robustness and potential applicability in other critical and high-stress environments.