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Open AccessArticle

Interactive Effects of Rarefaction and Surface Roughness on Aerodynamic Lubrication of Microbearings

by Yao Wu 1,2,3, Lihua Yang 1,2,3,*, Tengfei Xu 1,2,3 and Haoliang Xu 1,2,3
1
State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an 710049, China
2
Shaanxi Key Laboratory of Environment and Control for Flight Vehicle, Xi’an 710049, China
3
School of Aerospace Engineering, Xi’an Jiaotong University, Xi’an 710049, China
*
Author to whom correspondence should be addressed.
Micromachines 2019, 10(2), 155; https://doi.org/10.3390/mi10020155
Received: 30 January 2019 / Revised: 18 February 2019 / Accepted: 22 February 2019 / Published: 25 February 2019
(This article belongs to the Special Issue Gas Flows in Microsystems)
The aerodynamic lubrication performance of gas microbearing has a particularly critical impact on the stability of the bearing-rotor system in micromachines. Based on the Duwensee’s slip correction model and the fractal geometry theory, the interactive effects of gas rarefaction and surface roughness on the static and dynamic characteristics were investigated under various operation conditions and structure parameters. The modified Reynolds equation, which governs the gas film pressure distribution in rough bearing, is solved by employing the partial derivative method. The results show that high values of the eccentricity ratio and bearing number tend to increase the principal stiffness coefficients significantly, and the fractal roughness surface considerably affects the ultra-thin film damping characteristics compared to smooth surface bearing. View Full-Text
Keywords: gaseous rarefaction effects; fractal surface topography; modified Reynolds equation; aerodynamic effect; bearing characteristics gaseous rarefaction effects; fractal surface topography; modified Reynolds equation; aerodynamic effect; bearing characteristics
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Wu, Y.; Yang, L.; Xu, T.; Xu, H. Interactive Effects of Rarefaction and Surface Roughness on Aerodynamic Lubrication of Microbearings. Micromachines 2019, 10, 155.

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