Sim, Kyuho Lee, Yong-Bok Kim, Tae Ho 2024-01-20T09:02:01Z 2024-01-20T09:02:01Z 2021-09-05 2014-09 1040-2004 https://pubs.kist.re.kr/handle/201004/126389 This article presents the predictions of the rotordynamic performance of oil-free turbochargers (TCs) for various lobed gas foil bearings (GFBs) with the first-generation bump-type configuration and compares these predictions to the measured test data reported earlier. The three-lobed GFBs used for the simulations have increased bearing clearances and mechanical preloads with a fixed minimum bearing clearance, thus yielding larger average bearing clearances and higher wedge effects at the same time. The engine-induced TC housing excitation is found to have no influence on the critical speeds and damping ratios of the rotor rigid modes. The synchronous and asynchronous GFB analyses imply decreases in destabilizing forces for the highly lobed GFBs. The predicted critical speed and damping ratio of the TC rotor supported on the lobed GFBs demonstrate increasing system natural frequency and enhanced rotordynamic stability with increasing mechanical preload. The rotordynamic and bearing analyses of the lobed GFBs validate the beneficial effects of the mechanical preload on the rotordynamic stability of GFBs even with an increased average bearing clearance, which leads to a decreased bearing friction torque as well. English TAYLOR & FRANCIS INC DYNAMIC PERFORMANCE MECHANICAL PRELOAD THRUST BEARING STIFFNESS Rotordynamic Analysis of an Oil-Free Turbocharger Supported on Lobed Gas Foil Bearings-Predictions versus Test Data Article 10.1080/10402004.2014.937885 1 TRIBOLOGY TRANSACTIONS, v.57, no.6, pp.1086 - 1095 TRIBOLOGY TRANSACTIONS 57 6 1086 1095 scie scopus 000345317900014 2-s2.0-84907996452 Engineering, Mechanical Engineering Article DYNAMIC PERFORMANCE MECHANICAL PRELOAD THRUST BEARING STIFFNESS Gas Foil Bearing Lobe Bearing Oil-Free Turbocharger Rotordynamic Analysis Rotordynamic Stability