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Research Papers: Hydrodynamic Lubrication

Transient Analysis of the Textured Journal Bearing Operating With the Piezoviscous and Shear-Thinning Fluids

[+] Author and Article Information
Chunxing Gu

School of Mechanical Engineering,
Shanghai Jiaotong University,
Shanghai 200240, China
e-mail: chunxinggu@hotmail.com

Xianghui Meng

School of Mechanical Engineering,
Shanghai Jiaotong University,
Shanghai 200240, China
e-mail: xhmeng@sjtu.edu.cn

Di Zhang

School of Mechanical Electronic Technology,
Shanghai JianQiao University,
Shanghai 201306, China

Youbai Xie

School of Mechanical Engineering,
Shanghai Jiaotong University,
Shanghai 200240, China

1Corresponding author.

Contributed by the Tribology Division of ASME for publication in the JOURNAL OF TRIBOLOGY. Manuscript received August 19, 2016; final manuscript received January 12, 2017; published online May 26, 2017. Editor: Michael Khonsari.

J. Tribol 139(5), 051708 (May 26, 2017) (20 pages) Paper No: TRIB-16-1270; doi: 10.1115/1.4035812 History: Received August 19, 2016; Revised January 12, 2017

In this paper, a mixed lubrication model is presented to analyze the tribological behavior of the textured journal bearings operating from mixed to hydrodynamic lubrication regimes. In particular, the effects of fluid piezoviscosity and the non-Newtonian fluid behavior are also considered. The presented model solves the hydrodynamic lubrication problem by a mass-conserving formation of the Reynolds equation, whereas the metal–metal contact is considered by using the Greenwood and Tripp (GT) contact model which is linked with the hydrodynamic model based on the concept of Johnson's load sharing. As a result, the performance of the textured journal bearing system under different lubrication regimes, including boundary lubrication regime, mixed hydrodynamic lubrication regime, and hydrodynamic lubrication regime, can be evaluated. Using the journal bearing systems operated under the start-up condition as examples, prediction demonstrates the influences of texture distributions on friction and wear. It is found that the friction reducing effect induced by texturing is influenced by the distribution of the texturing zones. In particular, the hydrodynamic friction can be reduced when the eccentricity ratio is changed from high to low. Moreover, it appears that the shear-thinning effect of lubricant cannot be neglected in the transient analysis of journal bearing system.

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References

Figures

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Fig. 2

Schematic diagram for the groove textured journal bearing (transverse grooves)

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Fig. 3

The shear-thinning behavior of SAE 5W30 oil, whose temperature is 313 K

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Fig. 4

The variation of asperity contact pressure and real contact area fraction with the clearance

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Fig. 1

Schematic diagram of the journal bearing system

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Fig. 5

The grid points in the circumferential and axial directions

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Fig. 13

(a) The distribution of hydrodynamic pressure for case A0, whose eccentricity ratio is 0.7; (b) the distribution of hydrodynamic pressure for case B0, whose eccentricity ratio is 0.7; and (c) the pressurized zones for different texturing cases, whose eccentricity ratio is 0.7

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Fig. 7

Different cases for the fully texturing configuration and partial texturing configurations

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Fig. 8

Comparison results for the infinitely long journal bearing system: (a) the eccentricity ratio is 0.93 and (b) the eccentricity ratio is 0.95

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Fig. 9

Comparison results for the dynamically loaded journal bearing system: (a) the various displacement of journal center along the X component and (b) the various displacement of journal center along the Y component

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Fig. 10

(a) The friction coefficient values for different cases, when the eccentricity ratio is 0.2; (b) the change of friction reducing percentages for different texturing cases with the eccentricity ratio of 0.2 in consideration, in which the results from case A0 are used as references. When the value of the friction reducing percentage is negative, it means that the friction is reduced; otherwise, the friction is increased.

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Fig. 11

(a) The friction coefficient values for different cases, when the eccentricity ratio is 0.7; (b) the change of friction reducing percentages for different texturing cases with the eccentricity ratio of 0.7 in consideration, in which the results from case A0 are used as references. When the value of the friction reducing percentage is negative, it means that the friction is reduced; otherwise, the friction is increased.

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Fig. 21

The various peak wear load for different cases, involving fully texturing case and partial texturing cases

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Fig. 12

(a) The distribution of hydrodynamic pressure for case A0, whose eccentricity ratio is 0.2; (b) the distribution of hydrodynamic pressure for case B0, whose eccentricity ratio is 0.2; and (c) the pressurized zones for different texturing cases, whose eccentricity ratio is 0.2

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Fig. 6

The computational flow chart

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Fig. 14

(a) Various engines speeds during normal operating and initial engine start-up [41] and (b) the assumed sliding speed curves of shaft during the start-up process

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Fig. 15

(a) The relationship between the X component of applied load and crank angle, and (b) the relationship between the Y component of applied load and crank angle

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Fig. 16

(a) The various displacements of journal center (Xc(t), Yc(t)) along the X and Y components with crank angle and (b) the orbit of the journal center during the start-up process

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Fig. 17

(a) Shear rate of the lubricating film during the start-up process for case A0 and (b) the simulation results about power loss for case A0, in which the shear-thinning effect of lubricant is considered or not

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Fig. 18

(a) The variation of average viscosity value during the start-up process for case A0 and (b) the simulation results about power loss for case A0, in which the piezoviscous effect is considered or not

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Fig. 19

The acceleration results for case A0 and case B0: (a) the variations of acceleration along the X direction; (b) the variations of acceleration along the Y direction; (c) the results of acceleration along the X direction in the fifth cycle; and (d) the results of acceleration along the Y direction in the fifth cycle

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Fig. 20

The various energy loss for different texturing cases, including fully texturing case and partial texturing cases

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Fig. 22

The comparison result between case A0 and case B4: (a) the variation of the asperity contact friction with crank angles; (b) the variation of the hydrodynamic friction with crank angles; (c) the variation of the total friction with crank angles; and (d) the variation of power loss with crank angles

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Fig. 23

The comparison results between case A0 and case B4: (a) the variation of the X component of asperity contact force; (b) the variation of the Y component of asperity contact force

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Fig. 24

(a) Wear load profile for case A0 and (b) wear load profile for case B4

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