Transient and Steady State Vibration Analysis of a Wavy Thrust Bearing

2005 ◽  
Vol 128 (1) ◽  
pp. 139-145 ◽  
Author(s):  
H. Zhao ◽  
F. K. Choy ◽  
M. J. Braun
Keyword(s):  
Steady State ◽  
Vibration Analysis ◽  
Thrust Bearing ◽  
Numerical Procedure ◽  
Operating Conditions ◽  
System Stability ◽  
Thrust Bearings ◽  
External Perturbations ◽  
Vibration Signature ◽  
Transient And Steady State

This paper describes a numerical procedure for analyzing the dynamics of transient and steady state vibrations in a wavy thrust bearing. The major effects of the wavy geometry and the operating parameters on the dynamic characteristics of the bearing had been discussed in a previous paper; the present paper thus concentrates on examining the relationships between the development of the transient and steady state vibrations when operating conditions are parametrically varied. Special attention is given to the development of steady state vibrations from initial transients with comparisons and consequences to the overall system stability. Numerical based vibration signature analysis procedures are then used to identify and quantify the transient vibrations. The conclusions provide general indicators for designing wavy thrust bearings that are less susceptible to transients induced by external perturbations.

Transient and Steady State Vibration Analysis of a Wavy Thrust Bearing

2004 ◽  
Author(s):  
Hongmei Zhao ◽  
F. K. Choy ◽  
M. J. Braun
Keyword(s):  
Steady State ◽  
Vibration Analysis ◽  
Thrust Bearing ◽  
Numerical Procedure ◽  
Operating Conditions ◽  
System Stability ◽  
Thrust Bearings ◽  
External Perturbations ◽  
Vibration Signature ◽  
Transient And Steady State

This paper describes a numerical procedure for analyzing the dynamics of transient and steady state vibrations in a wavy thrust bearing. The major effects of the wavy geometry and the operating parameters on the dynamic characteristics of the bearing had been discussed in previous work. The present study thus concentrates on examining the relationships between the development of the transient and steady state vibrations when operating conditions including rotational speed and load magnitude are parametrically varied. Special attention is given to the development of steady state vibrations from initial transients with comparisons and consequences to the overall system stability. Numerical based vibration signature analysis procedures are then used to identify and quantify the transient vibrations. The conclusions provide general indicators for designing wavy thrust bearings that are less susceptible to transients induced by external perturbations.

An Accurate Solution of the Gas Lubricated, Flat Sector Thrust Bearing

1977 ◽  
Vol 99 (1) ◽  
pp. 82-88 ◽  
Author(s):  
I. Etsion ◽  
D. P. Fleming
Keyword(s):  
Film Thickness ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Thickness Distribution ◽  
Maximum Load ◽  
Accurate Solution ◽  
Operating Conditions ◽  
Thrust Bearings ◽  
Practical Design ◽  
Minimum Film Thickness

A flat sector shaped pad geometry for gas lubricated thrust bearings is analyzed considering both pitch and roll angles of the pad and the true film thickness distribution. Maximum load capacity is achieved when the pad is tilted so as to create a uniform minimum film thickness along the pad trailing edge. Performance characteristics for various geometries and operating conditions of gas thrust bearings are presented in the form of design curves. A comparison is made with the rectangular slider approximation. It is found that this approximation is unsafe for practical design, since it always overestimates load capacity.

Numerical prediction of the performance of gas-lubricated spiral groove thrust bearings

1997 ◽  
Vol 211 (2) ◽  
pp. 117-128 ◽  
Author(s):  
Y Yue ◽  
T. A. Stolarski
Keyword(s):  
Control Volume ◽  
Numerical Procedure ◽  
Operating Conditions ◽  
Hydrodynamic Bearings ◽  
Thrust Bearings ◽  
Flow Balance ◽  
Control Volumes ◽  
Volume Method ◽  
Spiral Angle ◽  
Spiral Grooves

The objective of this paper is to develop an accurate numerical procedure for the analysis of nominally flat contacts with spiral grooves lubricated by gases. The numerical procedure, which is based on the control-volume method, enables the solutions of the non-linear Reynolds equation to be obtained without limitation in geometry and operating conditions. Satisfactory flow balance was achieved on the control volumes as well as on the whole boundary and the method was proved to be very accurate. Convergence of the method was quick for any compressibility number. Three types of contact with spiral grooves were analysed. They were hydrodynamic bearings without interior chambers, hydrodynamic bearings with interior chambers and hybrid bearings. The effects of spiral angle, groove geometry (length, depth and width) and compressibility on performances were investigated for all possible designs.

Gas Purging System to Extend Thrust Bearing Life in ESPs

2021 ◽  
Author(s):  
Jose Caridad ◽  
Arthur Watson ◽  
Song Shang ◽  
Eric Nguyen ◽  
Gocha Chochua
Keyword(s):  
Thrust Bearing ◽  
Operating Conditions ◽  
Design Parameters ◽  
Motor Oil ◽  
Oil Viscosity ◽  
Test Fixture ◽  
Thrust Bearings ◽  
Working Volume ◽  
Gas Purging ◽  
Critical Components

Abstract Electric submersible pump (ESP) systems use thrust bearings in the seal section to handle the thrust generated by the pump stages. Thrust bearings are subjected to harsh operating conditions, including high loads, poor oil circulation, and motor oil viscosity degradation. A less-recognized issue is gas becoming centrifugally trapped under the thrust runner. The gas may be present because of incomplete purging of air during filling, permeation of well gas into the motor oil, or gradual gasification of motor oil at high temperatures. Because thrust bearings are such critical components, it is of interest to increase their reliability, which in turn will increase ESP life. A novel gas purging system (GPS) was designed to alleviate stressors on thrust bearings, including gas accumulation, viscosity deterioration and gasification at high temperature, and low working oil volume. GPS circulates oil along with any gas that accumulates under the thrust runner up to a quiet separation chamber. Degassed oil circulates back to the thrust bearing, while accumulated gas eventually purges to the wellbore through relief valves on subsequent on/off cycles. GPS also improves viscosity and reduces gasification by cooling the oil, and it provides a greater working volume of thrust bearing oil to reduce the effects of oil deterioration. This paper details the GPS design principles as well as the optimization of the different design parameters that affect its performance conducted via computational fluid dynamics (CFD). Observations captured on a test fixture built using the final configuration are also presented, validating the intended functionality.

Some Effects of Start-Up and Shut-Down on Thrust Bearing Assemblies in Hydro-Generators

2003 ◽  
Vol 125 (4) ◽  
pp. 824-832 ◽  
Author(s):  
C. M. Ettles ◽  
J. Seyler ◽  
M. Bottenschein
Keyword(s):  
Thrust Bearing ◽  
Operating Conditions ◽  
Transient Effects ◽  
Design Studies ◽  
Thrust Bearings ◽  
Beneficial Effects ◽  
Start Up ◽  
Thermal Bending ◽  
Run Up ◽  
Basic Studies

The modernization of hydro-generators can involve the analysis of many different manufacturer’s designs of thrust bearings. Recent designs of bearing in common use are very reliable, but when failures do occur, it is often with older machines and within the first few minutes of start-up. This paper is a result of general design studies of various thrust bearing configurations subjected to transient operating conditions. It is shown that transient effects can induce an ‘overshoot’ of thermal deformation which can become unstable, leading to ‘thermal ratchetting.’ Examples are given of pads of various manufacturer’s bearings that have been subjected to this mechanism. Results from operating turbines, basic studies and measurements of the thermal bending of plates indicate that a peak deflection occurs well before thermal equilibrium is attained. The peaking phenomenon may be obscured in some designs or in cases where the run-up is gradual. The beneficial effects of using an oil-lift system during start-up are described. During shut-down it is important that the contact of hot, crowned pads against the runner be prevented. Minimum times for operation of the lift system are suggested, based on the thickness of the pads.

Enhancement of Turning Process Using Vibration Signature Analysis

2005 ◽  
Author(s):  
Marlon C. Batey ◽  
Hamid R. Hamidzadeh
Keyword(s):  
Manufacturing Process ◽  
Vibration Analysis ◽  
Manufacturing System ◽  
Cutting Tool ◽  
Operating Conditions ◽  
Turning Process ◽  
Analysis Problem ◽  
Frequency Domains ◽  
Vibration Signature ◽  
Vibration Signatures

Analytical and experimental vibration analyses are conducted for a lathe system to detect the possibility of faults and develop an accurate cutting process. The data acquisition system utilized for this purpose processes the analog input from the manufacturing system and displays the response in both the real time and frequency domains. The vibration signatures for different arrangements are recorded to determine the dynamic characteristics of the system which includes work pieces, tool, and lathe components. These vibration signatures were analyzed to determine cause of inaccuracy in the manufacturing process and the faulty components. In this study, two major problem causing sources were identified using vibration analysis for the system under different operating conditions. In addition to the identified problems, the phenomena of cutting tool chatter with various intensities was examined and recorded during testing. In this study the best possible operating conditions for a specific turning process were determined using vibration analysis. Problem causing components for several case studies (different speeds, feed rates, and tool lengths) were identified and guidelines for improving a typical manufacturing process were recommended.

Static and Dynamic Performance of an Infinite Stiffness Hydrostatic Thrust Bearing

1977 ◽  
Vol 99 (1) ◽  
pp. 106-112 ◽  
Author(s):  
N. Tully
Keyword(s):  
Steady State ◽  
Vibration Analysis ◽  
Thrust Bearing ◽  
Dynamic Performance ◽  
Cone Angle ◽  
Vibration Absorber ◽  
Static Stiffness ◽  
Load Range ◽  
Normal Diaphragm ◽  
Steady State Performance

A novel form of variable hydrostatic restriction is proposed which will automatically achieve a high, infinite or negative static stiffness over a substantial load range. The restrictor is formed between the bearing body and a spring mounted conical plug. The steady state performance is analyzed and design curves presented which are valid for any cone angle from zero, i.e., fixed clearance, to 90 deg which is the normal diaphragm restrictor. The dynamic response to forced sinusoidal vibrations is examined in conventional vibration analysis form and it is found that the restrictor system may be designed to act as a vibration absorber.

Asymptotic Analysis of a Narrow Gas-Lubricated, Flat Sector Thrust Bearing

1988 ◽  
Vol 110 (3) ◽  
pp. 427-433 ◽  
Author(s):  
J. J. Shepherd
Keyword(s):  
Steady State ◽  
Numerical Methods ◽  
Power Loss ◽  
Thrust Bearing ◽  
Center Of Pressure ◽  
Operating Conditions ◽  
Load Bearing Capacity ◽  
Steady State Operation ◽  
Bearing Number ◽  
Continuous Range

The method of matched expansions is employed to analyze the steady state operation of a finite gas-lubricated flat sector bearing for the case where the ratio of radial to circumferential dimensions is small and the relevant bearing number, Λ, is moderate. This technique yields general expressions for the pressure distribution, load bearing capacity, power loss and center of pressure location that are valid for a significant and continuous range of bearing dimensions, orientations and operating conditions. Comparisons are made, where possible, with the existing results from the literature obtained by numerical methods.

Steady State Performance Characteristics of a Tilting Pad Thrust Bearing

2000 ◽  
Vol 123 (3) ◽  
pp. 608-615 ◽  
Author(s):  
Sergei B. Glavatskikh
Keyword(s):  
Steady State ◽  
Film Thickness ◽  
Thrust Bearing ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
Shaft Speed ◽  
Oil Film ◽  
Tilting Pad ◽  
Bearing Load ◽  
Steady State Performance

The paper reports results of the experimental investigation into the steady state performance characteristics of a tilting pad thrust bearing typical of design in general use. Simultaneous measurements are taken of the pad and collar temperatures, the pressure distributions, oil film thickness, and power loss as a function of shaft speed, bearing load, and supplied oil temperature. The effect of operating conditions on bearing performance is discussed. A small radial temperature variation is observed in the collar. A reduction in minimum oil film thickness with load is approximately proportional to p−0.6, where p is an average bearing pressure. It has also been found that the oil film pressure profiles change not only due to the average bearing load but also with an increase in shaft speed and temperature of the supplied oil.

Analysis of Starved Thrust Bearings Including Temperature Effects

1987 ◽  
Vol 109 (3) ◽  
pp. 395-401 ◽  
Author(s):  
A. Artiles ◽  
H. Heshmat
Keyword(s):  
Film Thickness ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Operating Conditions ◽  
Geometrical Parameters ◽  
Two Dimensional ◽  
Thrust Bearings ◽  
Direct Iteration ◽  
Finite Thrust ◽  
Raphson Iteration

A method of analysis is described treating starvation in finite thrust bearing pads. A variable-size finite difference mesh is used to represent the two-dimensional temperature and pressure fields. A combination of Newton-Raphson iteration, direct iteration, and column matrix methods are used to solve for the start-of-film and minimum film thickness as well as the coupled two-dimensional energy and Reynolds equations. A parametric study describes the performance characteristics of the tapered land thrust bearing (flowrates, extent of fluid film, temperature rises, load capacity and torque) for different minimum film thicknesses and levels of starvation. This study considered variations in the geometrical parameters such as pad aspect ratio (L/R2=1/3, 1/2, 2/3) and extent of the pad (β=27, 42, and 57 deg) with an optimum taper ratio (β1/β=0.8). It is found that the effects of starvation are fairly small near the flooded condition but accelerate rapidly below the 50 percent starvation level. The start of the film (θ1) depends mostly on the level of starvation, and is essentially independent of the geometrical parameters, operating conditions or film thickness.

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