Analysis of the Steady State Characteristics of Gas-Lubricated, Porous Journal Bearings

Sun, Dah-chen

doi:10.1115/1.3452533

Cited by 25 publications

(12 citation statements)

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“…By way of checking the accuracy of the results of floating-ring journal bearing, the steady state characteristics of the plain porous journal bearing were obtained with the floating-ring computer software. These characteristics are compared with the data of Sun (12) in Table 1. It may be seen that the agreement between the two sets of data is excellent.…”

Section: Solve Equationmentioning

confidence: 99%

Externally-Pressurized Gas-Lubricated Floating-Ring Porous Journal Bearings: Part 1: Steady State Analysis

Malik

1984

Proceedings of the Institution of Mechanical Engineers, Part C:

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A new type of gas-lubricatedfloating-ring journal bearing in which thefixed bearing and the ring are both porous, has been conceived and analysed, theoretically, for the steady state Characteristics. Bearing characteristics are presented against two design parameters, namely, clearances ratio and permeability parameter. The comparison of these characteristics with those of externally-pressurized plain porous journal bearings shows that the new bearing represents, with its steady state performance, a distinctly advanced bearing design. NOTATIONThe dimensional quantities are represented by barred symbols. A symbol without a bar refers only to the non-dimensional quantity. radial clearance in plain bearing, clearance of the inner film when ring and journal are concentric (m) (Fig. 1) clearance of the outer film when ring and bearing are concentric (m) (Fig. 1) C2/C1, clearances ratioFixAy pa R2, film force components (N) hi C , , film thicknesses (m) hminC1, minimum film thickness (m) H , R , thicknesses of the ring and the bearing shell (m) [= 1, 21 subscripts for the inner and the outer clearance spaces, also for the ring and the bearing shell ambient pressure (N/m2) p i pa, pressures (subambient) in the clearance spaces (N/m2) pi* pa, pressures (subambient) in porous media of the ring and the bearing shell (N/m2) p , pa, supply pressure (N/m2) P, ijR4w2/C, , viscous frictional power loss (W) QpR2C, @/2A, gas supply to the bearing (kg/s) ri Hi, radially outward coordinates (m) (Fig. 1)journal radius (m) R , , , R , inner and outer radii of the ring (m) ( Fig. 1) ?;. ijR4W/C, , viscous frictional torques (Nm) ui R0, gas velocity in &direction (m/s) Wp, R2, bearing load capacity (N) coordinate axes (Fig. 1) ring centre coordinates with reference to the bearing centre (m) zi C, , radially inward coordinates (m) (Fig. 1) (XR, YR)C1 = ( -~q cos $ R , -6 2 sin $R)CI, The MS wus

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Section: Solve Equationmentioning

confidence: 99%

Externally-Pressurized Gas-Lubricated Floating-Ring Porous Journal Bearings: Part 1: Steady State Analysis

Malik

1984

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…electric motors, turbomachinery and high-precision instruments. Alth ough steady state characteristics for a single-layered porous gas bearing are availab le [3], analysis relating to a two-layered bearing is very limit ed. Cusano [4,5] gave an analytical solution for the performance characteristics of a two-layered porous bearing using oil as a lubricant and using short and long bearing approximations respectively.…”

Section: Introductionmentioning

confidence: 99%

Study of externally-pressurized gas-lubricated two-layered porous journal bearings: A steady state analysis

Saha

Majumdar

2002

Proceedings of the Institution of Mechanical Engineers, Part J:

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The steady state performance of gas-lubricated two-layered porous journal bearings is analysed theoretically by an iterative method considering three-dimensional flow through the porous matrix and two-dimensional flow in the bearing clearance. In the absence of any available data for two layers, the results obtained for a single layer have been compared with previous results and have been found to be in excellent agreement. The effect of supply pressure, bearing number, feeding parameter and length-diameter ratio on the static characteristics is investigated and presented in the form of design charts. It has been observed that two-layered porous bearings give higher load-carrying capacity than single-layered bearings.

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“…supply pressure (Pa) p 1 , p 2 pressures in porous material and bearing clearance (Pa) P dimensionless pressureˆ…p ¡ p a †=p a q mass¯owrate (kg/s) q r , q z , q y mass¯owrates in the r, z, y directions (kg/s) q v volume¯owrate (m 3 /s) Q mass¯ow reduction ratio r, z, y coordinates in the r, z, y directions r s radial thickness of porous material (m) r 0 radius of the bearing (m) r 1 outer radius of porous material (m) < gas constant T temperature (K) w load-carrying capacity (N) W dimensionless load-carrying capacitŷ w= …p s ¡ p a †DL ‰ Š Z dimensionless coordinate in the z directionˆz=L a parameter pertaining to a surface restrictorˆ…k 0 /k †/…dr s /r s † e c eccentricity ratio at the bearing end for coupled loadsˆe c L/…2h 0 † e s eccentricity ratio for symmetrical loadsˆe s /h 0 r 1 , r 2 densities of air in porous material and bearing clearance (kg/m 3 )…”

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confidence: 99%

Static characteristics of aerostatic porous journal bearings with a surface-restricted layer

Yoshimoto

Tozuka

Dambara

2003

Proceedings of the Institution of Mechanical Engineers, Part J:

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Graphite porous materials have been successfully used in an aerostatic bearing. This is because graphite porous materials have a lower permeability than porous metal, which makes it possible to achieve a higher stiffness in aerostatic bearings. However, aerostatic porous bearings have a disadvantage in that they are prone to cause pneumatic hammer instability. Therefore, a restricted layer which has a permeability lower than the bulk of the porous material is usually formed on the bearing surface to avoid this instability. In this paper, the static characteristics of aerostatic porous journal bearings with a surface-restricted layer are investigated theoretically and experimentally. In addition, the effects of a surface-restricted layer on the static characteristics are discussed for two types of loads, symmetrical and coupled. NOTATIONe c shaft displacement at the bearing end for coupled loads (m) e s shaft displacement for symmetrical loads (m) dr s thickness of a surface-restricted layer (m) ds thickness of end seal (m) D diameter of the shaft (m) h local bearing clearance (m) h 0 average bearing clearance (m) k permeability of the bulk of porous material (m 2 ) k 0 permeability of a restricted layer (m 2 ) L bearing length (m) L 1 width of circumferential air supply groove (m) m tilt moment (N m) M dimensionless tilt moment h 0 m= …p s ¡ p a †DL 2 £ ¤ p a ambient pressure (Pa) p s supply pressure (Pa) p 1 , p 2 pressures in porous material and bearing clearance (Pa) P dimensionless pressureˆ…p ¡ p a †=p a q mass¯owrate (kg/s) q r , q z , q y mass¯owrates in the r, z, y directions (kg/s) q v volume¯owrate (m 3 /s) Q mass¯ow reduction ratio r, z, y coordinates in the r, z, y directions r s radial thickness of porous material (m) r 0 radius of the bearing (m) r 1 outer radius of porous material (m) < gas constant T temperature (K) w load-carrying capacity (N) W dimensionless load-carrying capacitŷ w= …p s ¡ p a †DL ‰ Š Z dimensionless coordinate in the z directionˆz=L a parameter pertaining to a surface restrictorˆ…k 0 /k †/…dr s /r s † e c eccentricity ratio at the bearing end for coupled loadsˆe c L/…2h 0 † e s eccentricity ratio for symmetrical loadsˆe s /h 0 r 1 , r 2 densities of air in porous material and bearing clearance (kg/m 3 )

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Analysis of the Steady State Characteristics of Gas-Lubricated, Porous Journal Bearings

Cited by 25 publications

References 0 publications

Externally-Pressurized Gas-Lubricated Floating-Ring Porous Journal Bearings: Part 1: Steady State Analysis

Externally-Pressurized Gas-Lubricated Floating-Ring Porous Journal Bearings: Part 1: Steady State Analysis

Study of externally-pressurized gas-lubricated two-layered porous journal bearings: A steady state analysis

Static characteristics of aerostatic porous journal bearings with a surface-restricted layer

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