Analysis of a Finite Grooved Misaligned Journal Bearing Considering Cavitation and Starvation Effects

1990 ◽  
Vol 112 (1) ◽  
pp. 60-67 ◽  
Author(s):  
D. Vijayaraghavan ◽  
T. G. Keith
Keyword(s):  
Journal Bearing ◽  
Numerical Procedure ◽  
Diameter Ratio ◽  
Film Rupture ◽  
Supply Pressure ◽  
Starvation Effects ◽  
Inlet Conditions ◽  
Journal Misalignment ◽  
Length To Diameter Ratio

The effect of journal misalignment on the predicted performance of a finite grooved journal bearing is analyzed in this paper. The numerical procedure used incorporates a cavitation algorithm, which automatically predicts film rupture and reformation in the bearings. The misalignment considered varies in magnitude and direction with reference to the boundaries of the bearing. In addition to the misalignment, the effect of lubricant starvation at the groove is also considered and compared with flooded inlet conditions. The effects of various degrees of starvation, or higher lubricant supply pressure, bearing length to diameter ratio and groove size are also investigated.

The Effects of Oil Supply Pressure at different Groove Position on Temperature and Pressure Profile in Journal Bearing

2013 ◽  
Vol 66 (3) ◽  
Author(s):  
Mohamad Ali Ahmad ◽  
Salmiah Kasolang ◽  
R. S. Dwyer-Joyce ◽  
Aidah Jumahat
Keyword(s):  
Journal Bearing ◽  
Pressure Profile ◽  
Diameter Ratio ◽  
Radial Load ◽  
Oil Supply ◽  
Supply Pressure ◽  
Pressure Profiles ◽  
Hydrodynamic Journal Bearing ◽  
Temperature And Pressure ◽  
Length To Diameter Ratio

The effects of oil supply pressure on the temperature and pressure at different groove locations on a hydrodynamic journal bearing were investigated. A journal with a diameter of 100 mm and a ½ length-to-diameter ratio was used. The supply pressure was set to 0.2, 0.5, and 0.7 MPa at seven different groove locations, namely, -45°, -30°, -15°, 0°, +15°, +30°, and +45°. Temperature and pressure profiles were measured at speed values of 300, 500, and 800 rpm with 10 kN radial load. The results show that the change in oil supply pressure simultaneously reduced the temperature and increased the pressure profile.

Influence of Inlet Conditions on the Thermohydrodynamic State of a Fully Circumferentially Grooved Journal Bearing

2000 ◽  
Vol 123 (3) ◽  
pp. 525-532 ◽  
Author(s):  
P. S. Keogh ◽  
M. M. Khonsari
Keyword(s):  
Temperature Distribution ◽  
Energy Equation ◽  
Journal Bearing ◽  
Hydrodynamic Bearing ◽  
Simplified Approach ◽  
Supply Pressure ◽  
Axial Temperature ◽  
Viscosity Variation ◽  
Inlet Conditions

A thermohydrodynamic (THD) analysis of a fully circumferentially grooved hydrodynamic bearing is presented. The pressure distribution is obtained using the short bearing approximation taking into account the viscosity variation in the radial and circumferential coordinates. The axial temperature variation is also included by an axial averaging technique, which incorporates the supply pressure and film entry temperature in the energy equation. It is found that the determination of the lubricant temperature at the entry to the film plays an important role in the overall temperature distribution in the bearing. A simplified approach for determining this temperature is presented. An extensive set of experimental results performed by Maki and Ezzat (1980, ASME J. Lubr. Technol., 102, pp. 8–14) is used for validation purposes. The results show that mixing in the inlet groove may cause the film entry temperature to be significantly different from the nominal supply temperature and hence have a significant influence on the bearing temperature.

Study on Dynamic Characteristics of a Hydrostatic and Hydrodynamic Journal Bearings for Small Diameter Grinding Spindle

2012 ◽  
Vol 497 ◽  
pp. 99-104 ◽  
Author(s):  
Zhi Quan Hou ◽  
Wan Li Xiong ◽  
Xue Bing Yang ◽  
Ju Long Yuan
Keyword(s):  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Small Diameter ◽  
Diameter Ratio ◽  
Design Parameters ◽  
Eccentricity Ratio ◽  
Dynamic Coefficients ◽  
Supply Pressure ◽  
Stiffness Coefficients ◽  
Direct Stiffness

The dynamic characteristics of a hydrostatic and hydrodynamic journal bearing with two arrays of eight holes have been investigated theoretically by the three-dimensional Computational Fluid Dynamics (CFD) models with respect to equilibrium position. The various dynamic coefficients for design parameters, such as orifice diameter, length to diameter ratio, eccentricity ratio, supply pressure, and rotational speed, are analyzed systematically under the action of displacement disturbance and velocity disturbance which are considered by the User Definition Function (UDF) programs. Results show that the dynamic coefficients greatly affected by design parameters. The cross stiffness coefficients increase rapidly more than direct stiffness with an increase of length to diameter ratio and rotational speed. Conversely, the direct stiffness coefficients are larger than cross stiffness with an increase of supply pressure and eccentricity ratio. It indicates that the journal bearing with two arrays of eight holes is suitable for their applications to small diameter grinding spindle by the means of optimizing the operating parameters and the structural parameters in order to obtain a better dynamic characteristic.

Grid Transformation and Adaption Techniques Applied in the Analysis of Cavitated Journal Bearings

1990 ◽  
Vol 112 (1) ◽  
pp. 52-59 ◽  
Author(s):  
D. Vijayaraghavan ◽  
T. G. Keith
Keyword(s):  
Coordinate System ◽  
Journal Bearing ◽  
Numerical Procedure ◽  
Computer Time ◽  
Journal Bearings ◽  
Second Order ◽  
Film Rupture ◽  
Transformation Procedure ◽  
Grid Adaption ◽  
Induced Flow

An existing cavitation algorithm (a numerical procedure that automatically predicts film rupture and reformation in bearings) is modified in this paper. Second order upwinding is used to difference the shear induced flow terms in the cavitated region. A grid transformation procedure using a body fitted coordinate system and grid adaption techniques are applied to the algorithm. Four statically loaded finite journal bearing cases are analyzed. The results are compared with the results obtained using a conventional grid. The advantage of these methods is demonstrated by obtaining equal or better accuracy with a coarser grid and by the consumption of smaller amounts of computer time.

An Experimental Investigation of the Effect of Misalignment and Directionality on the Performance of an Externally-Pressurized, Orifice-Compensated Air Journal Bearing

1979 ◽  
Vol 101 (1) ◽  
pp. 28-37 ◽  
Author(s):  
P. H. Markho ◽  
S. S. Grewal ◽  
T. B. Stowell
Keyword(s):  
Experimental Investigation ◽  
Journal Bearing ◽  
Diameter Ratio ◽  
Performance Characteristics ◽  
Double Plane ◽  
Order Of Magnitude ◽  
Length To Diameter Ratio

The study described in this paper aims to quantify the effects of misalignment and directionality on the important performance characteristics of a double-plane admission bearing having a length to diameter ratio of unity. The results clearly demonstrate that misalignment does not seriously impair the bearing performance, as long as due allowance is made for its effect on clearance at the bearing ends. In practice, this impairment would rarely exceed 10 percent. The effect of directionality is also found to be of the same order of magnitude.

scholarly journals The Prediction of Liquid Film Journal Bearing Performance with a Consideration of Lubricant Film Reformation: Part 1: Theoretical Results

1985 ◽  
Vol 199 (2) ◽  
pp. 95-102 ◽  
Author(s):  
D Dowson ◽  
C M Taylor ◽  
A A S Miranda
Keyword(s):  
Liquid Film ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Lubricant Film ◽  
Supply Rate ◽  
Film Rupture ◽  
Supply Pressure ◽  
Wide Range ◽  
The Reformation ◽  
Theoretical Results

Analyses of liquid film journal bearings rarely consider the reformation of the lubricant film. This reformation normally takes place in the vicinity of a supply groove and is influenced by, amongst other parameters, the lubricant supply pressure. In a previous paper the authors have described in detail the implementation of an algorithm to locate automatically and efficiently the locus of film rupture and reformation boundaries using a digital computer. In the present paper results are presented for a wide range of important variables. In particular, the prediction of lubricant supply rate is studied carefully and compared with data presented in a widely used design aid which does not account in detail for the influence of film reformation.

The Effects of Oil Groove Position on Torque and Frictional Force in Hydrodynamic Journal Bearing

2013 ◽  
Vol 393 ◽  
pp. 907-912 ◽  
Author(s):  
Mohamad Ali Ahmad ◽  
Salmiah Kasolang ◽  
Rob Dwyer-Joyce ◽  
Mimi Azlina Abu Bakar
Keyword(s):  
Friction Coefficient ◽  
Experimental Work ◽  
Frictional Force ◽  
Power Loss ◽  
Journal Bearing ◽  
Diameter Ratio ◽  
Bearing Surface ◽  
Oil Supply ◽  
Supply Pressure ◽  
Hydrodynamic Journal Bearing

Axial groove is a common supply method of distributing lubricant within a journal bearing. Lubricant is generally fed at a specific supply pressure to ensure that the journal and the bearing surface are separated. Shearing action between lubricant and bearing parts creates frictions which contribute to power loss in journal bearing. In the present study, an experimental work was conducted to determine the effect of oil groove location on torque and frictional force in hydrodynamic journal bearing. A journal diameter of 100mm with a 12 length-to-diameter ratio was used. The oil supply pressure was set at 0.20 to 0.25 MPa. The groove was positioned at 3 different locations namely 00, +150and +300. Measurements of torque and frictional force were obtained for speed values of 300, 500 and 800 RPM at different radial loads. It was observed that the change in oil groove location has affected the fluid frictional force and friction coefficient to some extent.

Experimental Study of Oil Supply Pressure Effects on Bearing Friction in Hydrodynamic Lubrication

2013 ◽  
Vol 315 ◽  
pp. 977-981 ◽  
Author(s):  
Mohamad Ali Ahmad ◽  
Salmiah Kasolang ◽  
Rob Dwyer-Joyce
Keyword(s):  
Friction Coefficient ◽  
Frictional Force ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Diameter Ratio ◽  
Pressure Effects ◽  
Oil Supply ◽  
Supply Pressure ◽  
Bearing System ◽  
Bearing Friction

Journal bearing is widely applied in most of rotating machineries for transmission of large loads at mean speed of rotation. Friction caused by the shearing condition between journal, bearing and lubricant contribute to power loses in journal bearing system. In the present study, an experimental work was conducted to determine the effect of oil supply pressure on frictional force, friction coefficient and torque of a journal bearing. A journal diameter of 100 mm with a ½ length-to-diameter ratio was used. The oil supply pressure was set at three different values (0.3, 0.5, 0.7 MPa). Frictional force and friction coefficient results for 400, 600 and 800 RPM at different radial loads were obtained. It was observed that the change in oil supply pressure has affected the fluid frictional force and friction coefficient to some extent.

Machine learning-based performance analysis of two-axial-groove hydrodynamic journal bearings

2021 ◽  
pp. 135065012199289
Author(s):  
Biswajit Roy ◽  
Sudip Dey
Keyword(s):  
Journal Bearing ◽  
Journal Bearings ◽  
Hydrodynamic Performance ◽  
Support Vector ◽  
Oil Viscosity ◽  
Hydrodynamic Analysis ◽  
Supply Pressure ◽  
Input Parameters ◽  
Precise Prediction ◽  
Output Behavior

The precise prediction of a rotor against instability is needed for avoiding the degradation or failure of the system’s performance due to the parametric variabilities of a bearing system. In general, the design of the journal bearing is framed based on the deterministic theoretical analysis. To map the precise prediction of hydrodynamic performance, it is needed to include the uncertain effect of input parameters on the output behavior of the journal bearing. This paper presents the uncertain hydrodynamic analysis of a two-axial-groove journal bearing including randomness in bearing oil viscosity and supply pressure. To simulate the uncertainty in the input parameters, the Monte Carlo simulation is carried out. A support vector machine is employed as a metamodel to increase the computational efficiency. Both individual and compound effects of uncertainties in the input parameters are studied to quantify their effect on the steady-state and dynamic characteristics of the bearing.

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