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CLC number: TH117.2

On-line Access: 2009-11-30

Received: 2009-03-10

Revision Accepted: 2009-07-06

Crosschecked: 2009-11-17

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Journal of Zhejiang University SCIENCE A 2010 Vol.11 No.1 P.43-49


Effects of rarefaction on the characteristics of micro gas journal bearings

Author(s):  Hai-jun ZHANG, Chang-sheng ZHU, Ming TANG

Affiliation(s):  College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China; more

Corresponding email(s):   zhjzszs_537@hotmail.com, cszhu@hotmail.com

Key Words:  Reference Knudsen number, Rarefaction effect, Reynolds equation, Finite difference method (FDM)

Hai-jun ZHANG, Chang-sheng ZHU, Ming TANG. Effects of rarefaction on the characteristics of micro gas journal bearings[J]. Journal of Zhejiang University Science A, 2010, 11(1): 43-49.

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author="Hai-jun ZHANG, Chang-sheng ZHU, Ming TANG",
journal="Journal of Zhejiang University Science A",
publisher="Zhejiang University Press & Springer",

%0 Journal Article
%T Effects of rarefaction on the characteristics of micro gas journal bearings
%A Hai-jun ZHANG
%A Chang-sheng ZHU
%A Ming TANG
%J Journal of Zhejiang University SCIENCE A
%V 11
%N 1
%P 43-49
%@ 1673-565X
%D 2010
%I Zhejiang University Press & Springer
%DOI 10.1631/jzus.A0900141

T1 - Effects of rarefaction on the characteristics of micro gas journal bearings
A1 - Hai-jun ZHANG
A1 - Chang-sheng ZHU
A1 - Ming TANG
J0 - Journal of Zhejiang University Science A
VL - 11
IS - 1
SP - 43
EP - 49
%@ 1673-565X
Y1 - 2010
PB - Zhejiang University Press & Springer
ER -
DOI - 10.1631/jzus.A0900141

Given the definition of the reference Knudsen number for micro gas journal bearings, the range in the number is related to the viscosity of air at different temperatures. A modified reynolds equation for micro gas journal bearings based on Burgdorfer’s first-order slip boundary condition is proposed that takes into account the gas rarefaction effect. The finite difference method (FDM) is adopted to solve the modified reynolds equation to obtain the pressure profiles, load capacities and attitude angles for micro gas journal bearings at different reference Knudsen numbers, bearing numbers and journal eccentricity ratios. Numerical analysis shows that pressure profiles and non-dimensional load capacities decrease markedly as gas rarefaction increases. Attitude angles change conversely, and when the eccentricity ratio is less than 0.6, the attitude angles rise slightly and the influence of the reference Knudsen number is not marked. In addition, the effect of gas rarefaction on the non-dimensional load capacity and attitude angle decreases with smaller bearing numbers.

Darkslateblue:Affiliate; Royal Blue:Author; Turquoise:Article


[1] Beskok, A., Karniadakis, G.E., 1999. A model for flows in channels, pipes and ducts at micro and nano-scales. Nanoscale and Microscale Thermophysical Engineering, 3(1):43-77.

[2] Burgdorfer, A., 1959. The influence of the molecular mean free path on the performance of hydrodynamic gas lubricated bearings. Journal of Basic Engineering, 81(1):94-100.

[3] Gad-el-Hak, M., 1999. The fluid mechanics of microdevices—the freeman scholar lecture. Journal of Fluids Engineering, 121(1):5-33.

[4] Hsia, Y.T., Domoto, G.A., 1983. An experimental investigation of molecular rarefaction effects in gas lubricated bearings at ultra-low clearances. Journal of Lubrication Technology, 105(1):120-130.

[5] Huang, H., Meng, G.., Zhao, S., 2006. The effects of second-order slip flow on the steady performance of micro gas bearings. Chinese Journal of Theoretical and Applied Mechanics, 38(5):68-673 (in Chinese).

[6] Irvine, T.F., Liley, P.E., 1984. Steam and Gas Tables with Computer Equations. Academic Press, Orlando.

[7] Karniadakis, G.E., Beskok, A., 2005. Micro Flow Fundamentals and Simulation. Springer-Verlag, New York, USA.

[8] Kennard, E.H., 1938. Kinetic Theory of Gases. McGraw-Hill, New York, USA.

[9] Lee, Y., Kwak, H., Kim, C., Lee, N., 2005. Numerical prediction of slip flow effect on gas-lubricated journal bearings for MEMS/MST-based micro-rotating machinery. Tribology International, 38:89-96.

[10] Liu, L.X., Teo, C.J., Epstein, A.H., Spakovszky, Z.S., 2005. Hydrostatic gas journal bearings for micro-turbomachinery. Journal of Vibration and Acoustics, 127(2):157-164.

[11] Liu, L.X., Spakovszky, Z.S., 2007. Effects of bearing stiffness anisotropy on hydrostatic micro gas journal bearing dynamic behavior. Journal of Engineering for Gas Turbines and Power, 129(1):177-184.

[12] Mitsuya, Y., 1993. Modified Reynolds equation for ultra-thin film gas lubrication using 1.5-order slip flow model and considering surface accommodation coefficient. Journal of Tribology, 115:289-294.

[13] Myong, R.S., 2004. Gas slip models based on the Langmuir adsorption isotherm. Physics of Fluids, 16(1):104-117.

[14] Orr, D.J., 2000. Macroscale Investigation of High Speed Gas Bearing for MEMS Devices. PhD Thesis, Massachusettes Institute of Technology, USA.

[15] Piekos, E.S., Breuer, K.S., 1999. Pseudospectral orbit simulation of nonideal gas-lubricated journal bearings for microfabricated turbomachines. Journal of Tribology, 121(3):604-609.

[16] Piekos, E.S., Breuer, K.S., 2002. Manufacturing effects in microfabricated gas bearings: axially varying clearance. Journal of Tribology, 124(4):815-821.

[17] Schaaf, S.A., Chambre, P.L., 1958. Flow of Rarefied Gas, Part H of Fundamentals of Gas Dynamics. Princeton University Press, USA.

[18] Shen, Q., 2003. Rarefied Gas Dynamics. National Defense Industry Press, Beijing, China (in Chinese).

[19] Shen, S., Chen, G., Crone, R.M., Anaya-Dufresne, M., 2007. A kinetic-theory based first order slip boundary condition for gas flow. Physics of Fluids, 19:086101.

[20] Sun, Y.H., Chan, W.K., Liu, N., 2002. A slip model with molecular dynamics. Journal of Micromechanics and Microengineering, 12(3):316-322.

[21] Teo, C.J., Liu, L.X., Li, H.Q., Ho, L.C., Jacobson, S.A., Ehrich, F.F., Epstein, A.H., Spakovszky, Z.S., 2006. High-speed Operation of a Gas-bearing Supported MEMS Air Turbine. Proceedings of the STLE/ASME International Joint Tribology Conference, San Antonio, Texas, USA, p.1303-1314.

[22] Teo, C.J., Spakovszky, Z.S., Jacobson, S.A., 2008. Unsteady flow and dynamic behavior of ultrashort Lomakin gas bearings. Journal of Tribology, 130(1):011001.

[23] Wu, L., Bogy, D.B., 2003. New first and second order slip models for the compressible Reynolds equations. Journal of Tribology, 125:558-561.

[24] Wu, L., 2008. A slip model for rarefied gas flows at arbitrary Knudsen number. Applied Physics Letters, 93:253103.

[25] Zhou, J., Meng, G., Zhang, W., 2007. Characteristics of micro gas journal bearings. Journal of Vibration and Shock, 26(9):30-33 (in Chinese).

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