A semianalytical approach to nonlinear fluid film forces of a hydrodynamic journal bearing with two axial grooves

Abstract The viscous heat generation in the lubricant film of a hydrodynamic journal bearing causes a rise in temperature of the fluid film. Considering the influence of the temperature variation along and across the film, the performance of a journal bearing is investigated under adiabatic conditions for different values of thermal conductivity of the lubricant. In this analysis, the temperature of the journal surface has been chosen to ensure that there is no net heat transfer from the lubricant The results show that the variation of temperature across the film affects bearing performance significantly and that an increase in lubricant thermal conductivity enhances bearing performance.

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THERMOHYDRODYNAMIC PERFORMANCE OF A JOURNAL BEARING WITH 3D-SURFACE ROUGHNESS AND FLUID INERTIA EFFECTS

International Journal of Applied Research in Mechanical Engineering ◽

10.47893/ijarme.2012.1044 ◽

2012 ◽

pp. 243-249

Author(s):

E. SUJITH PRASAD ◽

T. NAGARAJU ◽

J. PREM SAGAR

Keyword(s):

Surface Roughness ◽

Journal Bearing ◽

Roughness Parameter ◽

Theoretical Work ◽

Fluid Film ◽

Fluid Inertia ◽

Inertia Effects ◽

3D Surface Roughness ◽

Load Carrying ◽

Hydrodynamic Journal Bearing

This theoretical work describe the combined influence of surface roughness, thermal and fluid-inertia effects on performance characteristics of hydrodynamic journal bearing. The average Reynolds equation that modified to include the surface roughness, viscosity variation due to temperature rise in lubricant fluid-film and fluid-inertia is used to obtain pressure field in the fluid-film. The matched solutions of modified average Reynolds, energy and conduction equations are obtained using finite element method and appropriate iterative schemes. The effects of surface roughness parameter, roughness orientation, and roughness characteristics of opposing surfaces on circumferential fluid-film pressure distribution, load carrying capacity and stability threshold speed of the bearing are studied by considering thermal and fluid-inertia effects.

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An Efficient Calculation Method of Nonlinear Fluid Film Forces in Journal Bearing

Tribology Transactions ◽

10.1080/10402000208982556 ◽

2002 ◽

Vol 45 (3) ◽

pp. 324-329 ◽

Cited By ~ 15

Author(s):

Zhaobo Chen ◽

Yinghou Jiao ◽

Songbo Xia ◽

Wenhu Huang ◽

Zhiming Zhang

Keyword(s):

Calculation Method ◽

Journal Bearing ◽

Fluid Film ◽

Efficient Calculation ◽

Nonlinear Fluid

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Dynamic Response of an Unbalanced Rigid Rotor Bearing System With a Nonlinear Hydrodynamic Force

Journal of Computational and Nonlinear Dynamics ◽

10.1115/1.4037995 ◽

2018 ◽

Vol 13 (9) ◽

Cited By ~ 4

Author(s):

Chandan Kumar ◽

Somnath Sarangi

Keyword(s):

Journal Bearing ◽

Hydrodynamic Force ◽

Rigid Rotor ◽

Rotor Speed ◽

Periodic Oscillations ◽

Speed Range ◽

Rotor Bearing ◽

Hydrodynamic Journal Bearing ◽

Nonlinear Fluid ◽

Bearing System

Planar dynamics of a rotor supported by long hydrodynamic journal bearing is investigated theoretically. An analytical model of the long journal bearing system is numerically integrated for analysis of fixed point and periodic oscillations. The nonlinearities in the system arise due to a nonlinear fluid film force acting on the journal. The influences of three dimensionless parameters, viz. bearing parameter, unbalance, and rotor speed, on the dynamic behavior of the rotor bearing system is studied and compared with the short journal bearing. For the same bearing parameter, short bearing has large operating speed compared to a long bearing. The results are presented in the form of a bifurcation diagram and Poincaré map of the oscillations based on numerical computation. The considered unbalanced system shows periodic, multiperiodic, and quasi-periodic motion in different speed range. Jumping phenomenon is also observed for a high value of bearing parameter with unbalance.

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Effect of Surface Roughness on the Pressure Generation in a Finite Rough Hydrodynamic Journal Bearing under Micropolar Lubrication in Steady-State

Reason-A Technical Journal ◽

10.21843/reas/2016/39-53/158775 ◽

2016 ◽

Vol 15 (0) ◽

pp. 39

Author(s):

Gautam Kumar ◽

Sujeet Kumar Jha ◽

Ujjal Baidya ◽

Santanu Das ◽

Sanjoy Das

Keyword(s):

Surface Roughness ◽

Steady State ◽

Journal Bearing ◽

Hydrodynamic Journal Bearing ◽

Micropolar Lubrication ◽

Effect Of Surface

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Improvement of Tilting-Pad Journal Bearing Operating Characteristics by Application of Eddy Grooves

Lubricants ◽

10.3390/lubricants9020018 ◽

2021 ◽

Vol 9 (2) ◽

pp. 18

Author(s):

Eckhard Schüler ◽

Olaf Berner

Keyword(s):

High Speed ◽

Journal Bearing ◽

Load Capacity ◽

Fluid Film ◽

Operating Characteristics ◽

Fluid Film Bearings ◽

Tilting Pad ◽

Bearing Load ◽

Bearing Loads ◽

Tilting Pad Journal Bearing

In high speed, high load fluid-film bearings, the laminar-turbulent flow transition can lead to a considerable reduction of the maximum bearing temperatures, due to a homogenization of the fluid-film temperature in radial direction. Since this phenomenon only occurs significantly in large bearings or at very high sliding speeds, means to achieve the effect at lower speeds have been investigated in the past. This paper shows an experimental investigation of this effect and how it can be used for smaller bearings by optimized eddy grooves, machined into the bearing surface. The investigations were carried out on a Miba journal bearing test rig with Ø120 mm shaft diameter at speeds between 50 m/s–110 m/s and at specific bearing loads up to 4.0 MPa. To investigate the potential of this technology, additional temperature probes were installed at the crucial position directly in the sliding surface of an up-to-date tilting pad journal bearing. The results show that the achieved surface temperature reduction with the optimized eddy grooves is significant and represents a considerable enhancement of bearing load capacity. This increase in performance opens new options for the design of bearings and related turbomachinery applications.

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Theoretical Condition for the Cxy=Cyx Relation in Fluid Film Journal Bearings

Journal of Tribology ◽

10.1115/1.3261942 ◽

1989 ◽

Vol 111 (3) ◽

pp. 426-429 ◽

Cited By ~ 4

Author(s):

T. Kato ◽

Y. Hori

Keyword(s):

Reynolds Equation ◽

Journal Bearing ◽

Journal Bearings ◽

Fluid Film ◽

Finite Width ◽

Damping Coefficients ◽

Dynamic Coefficients ◽

Cross Terms ◽

Linear Damping ◽

Theoretical Condition

A computer program for calculating dynamic coefficients of journal bearings is necessary in designing fluid film journal bearings and an accuracy of the program is sometimes checked by the relation that the cross terms of linear damping coefficients of journal bearings are equal to each other, namely “Cxy = Cyx”. However, the condition for this relation has not been clear. This paper shows that the relation “Cxy = Cyx” holds in any type of finite width journal bearing when these are calculated under the following condition: (I) The governing Reynolds equation is linear in pressure or regarded as linear in numerical calculations; (II) Film thickness is given by h = c (1 + κcosθ); and (III) Boundary condition is homogeneous such as p=0 or dp/dn=0, where n denotes a normal to the boundary.

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