Performance of the Partially Porous and the Fully Porous Aerostatic Journal Bearings with Incompressible Air Flow

Abstract:

This report presents a study on the performance of the fully porous and the partially porous aerostatic journal bearings. Based on the finite volume method and the pressure-velocity coupling scheme of the SIMPLE algorithm with the standard k-ε turbulent model, this study utilized the CFD software to solve the incompressible three dimensional Navier-Stokes equations to calculate the pressure of the flow field in the bearings. The effects of the size of the porous medium, the bearing gap, the eccentric ratio and the rotational speed of the spindle on the characteristics of the bearing such as the pressure distribution, the load carrying capacity and the stiffness were investigated. The computed results revealed that, when the spindle rotated at high speed, the effect of the dynamic pressure became dominant, while the effect of the static pressure became insignificant. Among the three types of journal bearings under investigation, the partially porous aerostatic journal bearing exhibited the highest ratio of output pressure to air volume flow rate. It indicated that, in terms of operational efficiency, the partially porous aerostatic journal bearing is superior to the fully porous aerostatic journal bearing.

• Periodical: Key Engineering Materials (Volume 625)
• Pages: 384-391
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.625.384
• Online since: August 2014
• Authors: Te Yen Huang*, Shao Yu Hsu, Bo Zhi Wang, Sheam Chyun Lin
• Keywords: Aerostatic Journal Bearing, Air Film, Load Carrying Capacity, Porosity, Porous Medium

References

[1] J. Prakash, S.K. Vij, Effect of velocity slip in axially undefined porous bearings, Wear 38 (1976) 245-263.

DOI: 10.1016/0043-1648(76)90074-0

[2] M. Szwarcman, R. Gorez, Design of aerostatic journal bearings with partially porous walls, Int. J. Mach. Tool Design Res. 18(2) (1978) 49-58.

DOI: 10.1016/0020-7357(78)90008-2

[3] N.S. Rao, B.C. Majumdar, Dynamic stiffness and damping coefficients of aerostatic porous journal bearings, J. Mech. Eng. Sci. 20(5) (1978) 291-296.

DOI: 10.1243/jmes_jour_1978_020_049_02

[4] N.S. Rao, Analysis of aerostatic porous journal bearings using the slip velocity boundary conditions, Wear 76(1) (1982) 35-47.

DOI: 10.1016/0043-1648(82)90114-4

[5] K.C. Singh, N.S. Rao, B.C. Majumdar, Effect of slip flow on the steady state performance of aerostatic porous journal bearings, J. Tribol. 106(1) (1984) 156-162.

DOI: 10.1115/1.3260856

[6] M. Malik, C.M. Rodkiewicz, On slip flow considerations in gas lubricated porous bearings, Trans. ASME J. Tribol. 106(4) (1984) 484-491.

DOI: 10.1115/1.3260969

[7] S. Yoshimoto, H. Tozuka, S. Dambara, Static characteristics of aerostatic porous journal bearings with a surface-restricted layer, Proc. I. Mech. Eng. Part J: J. Eng. Tribol. 217(2) (2003) 125-132.

DOI: 10.1243/13506500360603552

[8] M. Miyatake, S. Yoshimoto, J. Sato, Whirling instability of a rotor supported by aerostatic porous journal bearings with a surface-restricted layer, Proc. I. Mech. Eng. Part J: J. Eng. Tribol. 220(2) (2006) 95-103.

DOI: 10.1243/13506501jet89

[9] M. Miyatake, S. Yoshimoto, T. Chiba, A. Chiba, Instability of aerostatic journal bearings with porous floating bush at high speeds, Trans. JSME, Part C: 74(6) (2008) 1631-1639.

DOI: 10.1299/kikaic.74.1631

[10] B.E. Launde, D.B. Spalding, Lectures in mathematical models of turbulence, 1st ed., Academic Press, London, (1972).

[11] J.O. Hinze, Turbulence, McGraw-Hill, New York, (1975).

[12] G.S. Beavers, D.D. Joseph, Boundary conditions at a naturally permeable wall, J. Fluid Mech. 30(1) (1967) 197-207.

DOI: 10.1017/s0022112067001375