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RESEARCH PAPERS

# Modeling and Identification of Gas Journal Bearings: Externally Pressurized Gas Bearing Results

[+] Author and Article Information
V. Viktorov

Department of Mechanics,  Politecnico di Torino, C.so Duca degli Abruzzi, 24, 10129 Torino, Italyvladimir.viktorov@polito.it

G. Belforte

Department of Mechanics,  Politecnico di Torino, C.so Duca degli Abruzzi, 24, 10129 Torino, Italyguido.belforte@polito.it

T. Raparelli

Department of Mechanics,  Politecnico di Torino, C.so Duca degli Abruzzi, 24, 10129 Torino, Italyterenziano.raparelli@polito.it

J. Tribol 127(3), 548-556 (Mar 16, 2004) (9 pages) doi:10.1115/1.1924425 History: Received November 13, 2003; Revised March 16, 2004

## Abstract

Static and dynamic characteristics of externally pressurized gas journal bearings with four supply orifices positioned at the central cross section for rotating shaft displacements near the bearing center are investigated. Results for transfer functions and for gas-film coefficients derived using the developed mathematical model are compared with the results derived from numerical computations of a nonlinear distributed parameter model of the gas bearings. Averaging and corrective coefficients are elaborated. The results obtained demonstrate that analytical data are in good agreement with the numerical data for the wide range of parameters and the mathematical model developed makes the simple calculation of static and dynamic characteristics of this type of externally pressurized gas bearings possible. Derived analytical relations for transfer functions and for gas-film coefficients of gas bearings provide an efficient means for designing rotor-bearing systems.

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## Figures

Figure 1

Schematic diagram of the center plane of the journal bearing with the coordinate system

Figure 2

Dimensionless pressure p* distributions for externally pressurized gas bearings with p¯c=2 and p¯c=5, L∕D=0.5

Figure 3

Pressure p distributions for externally pressurized gas bearings with L∕D=0.5 and L∕D=2, p¯c=5

Figure 4

Pressure p distributions for externally pressurized gas bearings with Λ=0 (in the area with θ=0–150°) and Λ=50 (in the area with θ=150°–360°), L∕D=0.5 and p¯c=5

Figure 5

Dimensionless average pressure pm* distributions for externally pressurized gas bearings with p¯c=2 and p¯c=5, L∕D=0.5

Figure 6

Dimensionless average pressure pm** distributions for externally pressurized gas bearings with p¯c=2 and p¯c=5, L∕D=0.5

Figure 7

Dimensionless average pressure pm* distributions for externally pressurized gas bearings with L∕D=0.5 and L∕D=2, p¯c=5

Figure 11

Dimensionless average pressure squared pqm* distribution for externally pressurized gas bearings with p¯c=2 and p¯c=5, L∕D=0.5

Figure 12

Dimensionless average pressure squared pqm* distribution for externally pressurized gas bearings with L∕D=0.5 and L∕D=2, p¯c=5

Figure 13

Dimensionless average pressure squared pqm* distributions for externally pressurized gas bearings with Λ=0 and Λ=100, L∕D=0.5, p¯c=5 and p¯s=7

Figure 14

Cross-coupled dimensionless stiffness and damping coefficient externally pressurized gas bearings with annular supply orifices, Λ=5.27, p¯c=2, L∕D=0.5, and L∕D=4 (continuous lines: analytical model, dashed lines: numerical model)

Figure 15

Direct dimensionless stiffness and damping coefficient of externally pressurized gas bearings with annular supply orifices, Λ=5.27, p¯c=2, L∕D=0.5, and L∕D=4 (continuous lines: analytical model, dashed lines: numerical model)

Figure 16

Cross-coupled dimensionless stiffness and damping coefficient externally pressurized gas bearings with simple supply orifices, Λ=21.08, p¯c=5.3, L∕D=0.5, and L∕D=4 (continuous lines: analytical model, dashed lines: numerical model)

Figure 17

Direct dimensionless stiffness and damping coefficient of externally pressurized gas bearings with simple supply orifices, Λ=21.08, p¯c=5.3, L∕D=0.5, and L∕D=4 (continuous lines: analytical model, dashed lines: numerical model)

Figure 18

Cross-coupled dimensionless stiffness and damping coefficient externally pressurized gas bearings with annular supply orifices, Λ=100, p¯c=3, L∕D=1, and L∕D=2 (continuous lines: analytical model, dashed lines: numerical model)

Figure 19

Direct dimensionless stiffness and damping coefficient of externally pressurized gas bearings with annular supply orifices, Λ=100, p¯c=3, L∕D=1, and L∕D=2 (continuous lines: analytical model, dashed lines: numerical model)

Figure 20

Dimensionless static stiffness K¯ and attitude angle β for bearings with p¯c=1,3,5.3 and L∕D=0.5 (continuous lines: simple supply orifices, dashed lines: annular supply orifices)

Figure 21

Dimensionless static stiffness K¯ and attitude angle β for bearings with p¯c=1,3,5.3 and L∕D=1 (continuous lines: simple supply orifices, dashed lines: annular supply orifices)

Figure 22

Dimensionless static stiffness K¯ and attitude angle β for bearings with p¯c=1,3,5.3 and L∕D=2 (continuous lines: simple supply orifices, dashed lines: annular supply orifices)

Figure 8

Dimensionless average pressure pm** distributions for externally pressurized gas bearings with L∕D=0.5 and L∕D=2, p¯c=5

Figure 9

Dimensionless average pressure pm* distributions for externally pressurized gas bearings with Λ=0, Λ=12.5, and Λ=100, L∕D=0.5, p¯c=5 and p¯s=7

Figure 10

Dimensionless average pressure pm** distributions for externally pressurized gas bearings with Λ=0, Λ=12.5 and Λ=100, L∕D=0.5, p¯c=5 and p¯s=7

## Errata

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