Dynamic characteristics of grooved air bearings in microsystems

L. M. Chu, Wang-Long Li, R. W. Shen, T. I. Tsai

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

The performance of grooved air bearings in microsystems is analysed and discussed. The modified molecular gas lubrication (MMGL) equation is utilized as the governing equation for the gas film to include the effect of gas rarefaction. The gas rarefaction is significantly affected by two important parameters (Knudsen numbers (Kn) and accommodation coefficients (ACs)). The Poiseuille and Couette flowrate correctors (QP and QC) are introduced in the MMGL equation to extend the lubrication theory (compressible Reynolds equation) for arbitrary Kn and tangential momentum accommodation coefficients or ACs. At a specific operating condition, the transient MMGL equation is linearized by small variations in film thickness and pressure. The linearized MMGL equation is then solved by finite-element method to obtain the dynamic pressure distributions. Therefore, the dynamic coefficients (stiffness and damping coefficients) are obtained by integrating the dynamic pressure over the bearing surfaces.

Original languageEnglish
Pages (from-to)895-908
Number of pages14
JournalProceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology
Volume223
Issue number6
DOIs
Publication statusPublished - 2009 Sep 1

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Bearings (structural)
gas bearings
Microsystems
lubrication
dynamic characteristics
molecular gases
accommodation coefficient
Gases
Lubrication
Air
rarefaction
Knudsen flow
dynamic pressure
gases
Reynolds equation
coefficients
pressure distribution
stiffness
finite element method
film thickness

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

Cite this

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abstract = "The performance of grooved air bearings in microsystems is analysed and discussed. The modified molecular gas lubrication (MMGL) equation is utilized as the governing equation for the gas film to include the effect of gas rarefaction. The gas rarefaction is significantly affected by two important parameters (Knudsen numbers (Kn) and accommodation coefficients (ACs)). The Poiseuille and Couette flowrate correctors (QP and QC) are introduced in the MMGL equation to extend the lubrication theory (compressible Reynolds equation) for arbitrary Kn and tangential momentum accommodation coefficients or ACs. At a specific operating condition, the transient MMGL equation is linearized by small variations in film thickness and pressure. The linearized MMGL equation is then solved by finite-element method to obtain the dynamic pressure distributions. Therefore, the dynamic coefficients (stiffness and damping coefficients) are obtained by integrating the dynamic pressure over the bearing surfaces.",
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Dynamic characteristics of grooved air bearings in microsystems. / Chu, L. M.; Li, Wang-Long; Shen, R. W.; Tsai, T. I.

In: Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, Vol. 223, No. 6, 01.09.2009, p. 895-908.

Research output: Contribution to journalArticle

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