Performance Characteristics of an Innovative Journal Bearing With Adjustable Bearing Elements

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
R. Pai ◽  
D. W. Parkins
Keyword(s):  
Journal Bearing ◽  
Support Systems ◽  
Performance Characteristics ◽  
Experimental Results ◽  
Fluid Film ◽  
The Novel ◽  
Test Results ◽  
Static Characteristics ◽  
Fluid Film Bearings ◽  
Attitude Angle

The development of new machines capable of running at high loads and speeds is an important industrial requirement, which demands that the performance envelope of the support systems for these machines be extended. Conventional full cylindrical fluid film bearings may present instability problems at higher speeds and loads, which has been countered by the use of different bearing bore shapes. In this paper, the performance characteristics of a novel fluid film bearing, comprising of a number of adjustable bearing elements is presented. Experiments have been performed to measure the static characteristics of the novel bearing with different radial and tilt adjustments of the bearing elements. The test bearing has an L/D ratio of 0.53 and was run at 2000, 5000, and 7000 rpm. The load on the bearing was varied from 0 to 600 N. Eccentricity, attitude angle, temperature of oil; power absorbed; and stability are measured. Experimental results are compared with those for a conventional axial groove plain cylindrical bearing having the same L/D ratio and run under similar conditions. Test results indicate that the novel bearing is very stable at zero loads and at 8800 rpm. Typical results obtained are presented. A few of the attributes and features of the novel bearing are also presented.

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

Lubricants ◽  
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.

Magneto-rheological fluid slot-entry journal bearing considering thermal effects

2019 ◽  
Vol 30 (18-19) ◽  
pp. 2831-2852 ◽  
Author(s):  
Krishnkant Sahu ◽  
Satish C Sharma
Keyword(s):  
Thermal Effects ◽  
Journal Bearing ◽  
Fluid Model ◽  
Viscous Friction ◽  
Fluid Film ◽  
Applied Current ◽  
Bingham Model ◽  
Geometric Imperfection ◽  
Fluid Film Bearings ◽  
Magneto Rheological

In recent times, controlling the performance of fluid film bearings smartly has become an important area for the fluid film bearing designers. This study deals with the numerical simulation of a magneto-rheological fluid–lubricated two-lobe hybrid slot-entry journal bearing. To make the operating condition more exact and realistic, the influence of geometric imperfection of the journal arising from manufacturing inaccuracies and thermal effect has been considered. Dave magneto-rheological fluid model, a constitutive relation of the Bingham model, and finite element method have been used in this article to simulate the behavior of the magneto-rheological fluid in a slot-entry bearing. The results indicate that the heat generated because of viscous friction rises the temperature of the magneto-rheological fluid, which changes the bearing performance significantly. Considering barrel-shaped journal and magneto-rheological fluid (applied current, Ic = 4 A), the performance of two-lobe slot-entry bearing is superior in terms of the value of [Formula: see text] approximately by a magnitude of 2%, 41%, 181%, 168%, 75%, and 41%, respectively, as compared to that of the base bearing (smooth [Formula: see text], two-lobe bearing, operating with a Newtonian fluid, Ic = 0 A).

Hydrodynamic Performance Characteristics of a Fluid Film Journal Bearing With a Rectangular Jacking Pocket

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Michael Branagan ◽  
Neal Morgan ◽  
Christopher Goyne ◽  
Roger Fittro ◽  
Robert Rockwell ◽  
...  
Keyword(s):  
Journal Bearing ◽  
Pressure Profile ◽  
Fluid Film ◽  
Hydrodynamic Performance ◽  
Pocket Depth ◽  
Response Surface Models ◽  
Fluid Film Bearings ◽  
Surface Models ◽  
Computational Fluid Dynamics Cfd ◽  
Stiffness Characteristics

Abstract To compensate for an extremely heavy journal, jacking pockets can be added to the surface of pads in fluid film bearings. Jacking pockets can range in size and shape and will have an influence on the hydrodynamic performance of the bearing. Computational fluid dynamics (CFD) was used to better understand the influence of the geometry of a rectangular/stadium-shaped, jacking pocket on the performance of bearings. First, the influence of the pocket depth on the pressure profile of the bearing was investigated. A varying profile occurred with jacking pocket depths less than 6.6 × Cb. After this threshold, the pocket depth ceased to have an influence on the pressure profile. A second study examined the circumferential length of the pocket, and the pressure profile was found to approach the smooth case as the pocket circumferential length decreased. Response surface models were created to map the influence of the jacking pocket geometry on the journal location in the bearing, power loss, and stiffness characteristics of the bearing. This is the first study on influence of the geometry of a jacking pocket on the operation and linear stiffnesses of the bearing in fluid film journal bearings.

Confirmation Testing and Preliminary Dynamic Measurements of a Journal Bearing Test Rig

2008 ◽  
Author(s):  
J. Harrison Gyurko ◽  
Stephen A. Hambric ◽  
Karl M. Reichard
Keyword(s):  
Journal Bearing ◽  
Test Method ◽  
Fluid Film ◽  
Data Sets ◽  
Impedance Matrix ◽  
Pressure Measurements ◽  
Dynamic Measurements ◽  
Test Rig ◽  
Fluid Film Bearings ◽  
Force Transfer

Current modeling of the static and dynamic characteristics of fluid film bearings typically employs a single impedance matrix to represent the force transfer between a bearing and journal centerlines. A numerical method has been proposed that distributes the bearing impedances around the circumference of the fluid film to allow for more accurate modeling of higher order circumferential modes. In order for this method to be used with confidence, its results must first be validated. For this purpose, an experimental test method and apparatus capable of measuring these distributed bearing impedances has been developed. This paper will present the preliminary bearing displacement and pressure measurements collected from the journal bearing test apparatus and will compare these experimental results to those calculated numerically. Discrepancies between the data sets will be discussed and future steps will be outlined.

Separation Cavitation in Lightly Loaded Fluid Film Bearings with Both Surfaces in Motion

1974 ◽  
Vol 16 (3) ◽  
pp. 147-155 ◽  
Author(s):  
C. M. Taylor
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Experimental Work ◽  
Journal Bearing ◽  
Fluid Film ◽  
Operating Parameters ◽  
Separation Boundary ◽  
Fluid Film Bearings ◽  
Theoretical Predictions ◽  
Bounding Surfaces

For lightly loaded fluid film bearings in which gaseous cavitation occurs, application of the continuity boundary condition at the liquid-gas interface is not satisfactory. Two alternative boundary conditions have been postulated. The purpose of this paper is to examine the separation boundary condition; in particular, the effect of both bounding surfaces being in motion is studied. This situation might be used as a basis for experimental work designed to select the most appropriate boundary condition for lightly loaded bearings. In Part 2, the boundary condition is used to analyse the cylinder-plane and journal bearing configurations. The theoretical predictions for the operating parameters are examined to see if their magnitudes and/or trends could be used for comparing the available cavitation boundary conditions.

Experimental Verification of Subcritical Whirl Bifurcation of a Rotor Supported on a Fluid Film Bearing

1998 ◽  
Vol 120 (3) ◽  
pp. 605-609 ◽  
Author(s):  
J. C. Deepak ◽  
S. T. Noah
Keyword(s):  
Limit Cycle ◽  
Journal Bearing ◽  
Gradual Increase ◽  
Fluid Film ◽  
Subcritical Bifurcation ◽  
Supercritical Bifurcation ◽  
Fluid Film Bearings ◽  
Unbalanced Rotor ◽  
Single Disk ◽  
Sudden Jump

The paper presents the results of the experiments that were conducted on a short fluid film bearing with a simple single disk rotor. The behavior of the journal was analyzed as a function of the rotor system parameters such as the load, speed, and imbalance mass. It was verified that the journal bearing can lose stability through either a subcritical or a supercritical bifurcation. In the supercritical bifurcation, the expected gradual increase in the amplitude of the limit cycle was observed, while in the subcritical bifurcation there was a sudden jump to a large limit cycle. In the case of a subcritical bifurcation, it was also observed that the journal bearing became unstable below the rotor threshold speed of instability, following a small perturbation applied to the rotor. Demarcations were made for the stable regions of operation (regions where the rotor is stable below the threshold speed of instability) for the journal bearing based on the obtained experimental results. Experiments were also performed to analyze the effects of imbalance of the rotor on the threshold speed of instability. It was observed that the flexible unbalanced rotor had a lower threshold speed of instability. The limitations of the linear theory of fluid film bearings in predicting these phenomena are discussed.

Design and Development of Permanent Magneto-Hydrodynamic Hybrid Journal Bearing

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
K. P. Lijesh ◽  
Harish Hirani
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Magnetic Bearing ◽  
Operating Conditions ◽  
Fluid Film ◽  
Test Setup ◽  
Fluid Film Bearings ◽  
Lubrication Regime ◽  
Load Carrying ◽  
Hybrid Bearing

Fluid film bearings (FFBs) provide economic wear-free performance when operating in hydrodynamic lubrication regime. In all other operating conditions, except hydrostatic regime, these bearings are subjected to wear. To get wear-free performance even in those conditions, a hybrid (hydrodynamic + rotation magnetized direction (RMD) configured magnetic) bearing has been proposed. The hybrid bearing consists of square magnets to repel the shaft away from the bearing bore. Load-carrying capacities of four configurations of hybrid bearings were determined. The results are presented in this paper. The best configuration of hybrid bearing was developed. A test setup was developed to perform the experiments on the fluid film and hybrid bearings. The wear results of both the bearings under same operating conditions are presented.

scholarly journals Performance Characteristics of a Long Porous Partial Journal Bearing using Couple Stress Fluid

2019 ◽  
Vol 8 (4) ◽  
pp. 4235-4240
Keyword(s):  
Flow Rate ◽  
Couple Stress ◽  
Journal Bearing ◽  
Fluid Model ◽  
Performance Characteristics ◽  
Fluid Film ◽  
Couple Stress Fluid ◽  
Squeeze Film ◽  
Stress Parameter ◽  
Matlab Programming

After effects of studies led on a long porous partial journal bearing for couple stress fluid are thus displayed. Performance characteristics presently determined incorporate the time-height relationship, Fluid film force, Flow rate, frictional force alongside the coefficient of friction. Plan/Technique/Approach -The paper shows a solution for the squeeze film lubrication of a thick, porous, with couple stress fluid model. It is determined that the changed Reynolds condition inferred the fluid film pressures. The modified state of Reynolds equation is analytically solved and closed form expressions are shown for the time-height, the flow rate and friction force with frictional coefficient numerically with the given starting condition using MATLAB programming, the first non-linear equation in the time-height relationship is resolved. The effects on the squeeze film characteristics of couple stresses and permeability are discussed. Findings – It can be seen that the couple stress parameter enhances the bearing characteristics. The bearing performance can be improved with the increase of couple stress parameter ( l  ), eccentricity ratio (ϵ), permeability parameter (ψ). Additional study may be performed using the couple stress fluid model, including the magnetic effect with heat and mass transfer. This model can be used to compare further with other models such as micropolar fluid, rabinowitsch fluid and for comparative study, which models are the most suitable for improving bearing system performance.

A Study of Hole-Entry Grooved Surface Hybrid Spherical Journal Bearing Operating With Electrorheological Lubricant

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Adesh Kumar Tomar ◽  
Satish C. Sharma
Keyword(s):  
Journal Bearing ◽  
Fluid Film ◽  
Substantial Influence ◽  
The Finite Element Method ◽  
Bearing Surface ◽  
Stiffness Coefficients ◽  
Fluid Film Bearings ◽  
Grooved Surface ◽  
Fluid Film Thickness ◽  
Newtonian Behavior

Abstract The performances of the tribo-pairs are greatly influenced by introducing the grooved surfaces. Developments of the newer type of lubricants have made a great impact on the performance of fluid film bearings. This article investigates the non-Newtonian behavior of electrorheological lubricant on the performance of grooved hybrid spherical journal bearing. The effect of different arrangements of grooves, i.e., partially grooved or fully grooved on the bearing surface, has been studied. The finite element method is used to numerically simulate the results. Furthermore, a parametric study is performed for optimizing the groove attributes. The present work demonstrates that the different grooved arrangements have a substantial influence on the bearing performance. It is revealed that the provision of grooves on the bearing surface decreases frictional losses and enhances the stiffness coefficients of the bearing. Furthermore, numerically simulated results indicate that the electrorheological lubricant enhances the value of minimum fluid film thickness and the stiffness coefficients (S¯xxandS¯yy) of spherical hybrid journal bearing. Improved bearing performance can be achieved by using the optimized grooved attributes together with the electrorheological lubricant.

Reliability Improvement of Rotor Supports by Combining Rolling-Element Bearings and Fluid-Film Bearings

2014 ◽  
Vol 630 ◽  
pp. 188-198 ◽  
Author(s):  
Roman Polyakov ◽  
Leonid Savin ◽  
Denis Shutin
Keyword(s):  
Load Capacity ◽  
Life Time ◽  
Performance Characteristics ◽  
Fluid Film ◽  
Rolling Element Bearing ◽  
Rolling Element Bearings ◽  
Advantages And Disadvantages ◽  
Fluid Film Bearings ◽  
Rolling Element ◽  
Unit Increase

Reliability of rotating machinery is determined to a considerable degree by the bearing units. For several applications the requirements in rotation speed, bearing load and maximal vibration level are so extreme that neither rolling-element bearings nor fluid-film bearings could provide necessary performance characteristics during all regimes of operation. Hybrid bearings, which are a combination of rolling-element and fluid-film bearings, can improve performance characteristics and reliability of the rotor-bearing systems. The aim of this work is to analyze the advantages and disadvantages of the hybrid bearings. Known real applications of hybrid bearings are discussed. Analysis shows that depending on the application different hybrid bearing types could improve dynamic characteristics and life time of the bearing unit, increase load capacity and DN limit of the rolling-element bearing.

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