Research on the Static and Dynamic Characteristics of Misaligned Journal Bearing Considering the Turbulent and Thermohydrodynamic Effects

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Guohui Xu ◽  
Jian Zhou ◽  
Haipeng Geng ◽  
Mingjian Lu ◽  
Lihua Yang ◽  
...  
Keyword(s):  
Film Thickness ◽  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Static And Dynamic Characteristics ◽  
Oil Film ◽  
Stiffness And Damping ◽  
Film Stiffness ◽  
Journal Misalignment ◽  
Oil Film Pressure

Journal misalignment usually exists in journal bearings that affect nearly all the bearings static and dynamic characteristics including minimum oil film thickness, maximum oil film pressure, maximum oil film temperature, oil film stiffness, and damping. The main point in this study is to provide a comprehensive analysis on the oil film pressure, oil film temperature, oil film thickness, load-carrying capacity, oil film stiffness, and damping of journal bearing with different misalignment ratios and appropriately considering the turbulent and thermo effects based on solving the generalized Reynolds equation and energy equation. The results indicate that the oil thermo effects have a significant effect on the lubrication of misaligned journal bearings under large eccentricity ratio. The turbulent will obviously affect the lubrication of misaligned journal bearings when the eccentricity or misalignment ratio is large. In the present design of the journal bearing, the load and speed become higher and higher, and the eccentricity and misalignment ratio are usually large in the operating conditions. Therefore, it is necessary to take the effects of journal misalignment, turbulent, and thermal effect into account in the design and analysis of journal bearings.

Stability of Jeffcott Rotor Operating in Tilting 3-Pad Journal Bearings with Turbulent Oil Film

2009 ◽  
Vol 147-149 ◽  
pp. 450-455
Author(s):  
Stanislaw Strzelecki ◽  
Sobhy M. Ghoneam
Keyword(s):  
Theoretical Investigation ◽  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Oil Film ◽  
Temperature Distributions ◽  
Jeffcott Rotor ◽  
Oil Flow ◽  
The Stability ◽  
Oil Film Pressure

This paper introduces the results of theoretical investigation on the dynamic characteristics of tilting 3-pad journal bearing that operates with turbulent oil film. The Reynolds, energy, viscosity and geometry equations determine the oil film pressure, temperature distributions, and oil film resultant force that are the grounds for the dynamic characteristics of bearing. These equations were solved simultaneously on the assumption of adiabatic laminar or adiabatic turbulent oil flow in the bearing gap. The stability and system damping of Jeffcott rotor operating in tilting 3-pad journal bearing was determined.

Effect of Journal Misalignment on the Oil Film Pressure and Temperature Distribution of 3-Lobe Offset Journal Bearing

2005 ◽  
Author(s):  
S. Strzelecki ◽  
Z. Towarek
Keyword(s):  
Temperature Distribution ◽  
High Speed ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Good Stability ◽  
Rotating Machines ◽  
Film Pressure ◽  
Bearing Design ◽  
Journal Misalignment ◽  
Oil Film Pressure

The design of turbines and compressors operating at the high rotational speeds applies the 3-lobe journal bearings. In many cases the classic 3-lobe journal bearings supporting the rotors, are showing the problem of rotor stability. This problem can be avoided by the application of 3-lobe Offset bearings. This type of bearing fulfils the conditions of reliable bearing design and good stability in the case of high speed rotating machines.

Experimentally study of dynamic pressure distribution and oil film forces in journal bearing using ElectroMechanical Film sensor array

2019 ◽  
Vol 234 (4) ◽  
pp. 903-913
Author(s):  
Changmin Chen ◽  
Jianping Jing ◽  
Jiqing Cong ◽  
Chao Ji
Keyword(s):  
Pressure Distribution ◽  
Sensor Array ◽  
Journal Bearing ◽  
Dynamic Pressure ◽  
Vertical Direction ◽  
Journal Bearings ◽  
Film Sensor ◽  
Film Pressure ◽  
Oil Film ◽  
Oil Film Pressure

The acquisition of the oil film pressure and forces on the bearing pads through experimentation is crucial to understanding the characteristics of journal bearing. Lots of efforts had been taken in film pressure measurement, and the pressure was obtained at specified position on the bearing pads. However, due to the space and structure constraint, merely very limited number of the point pressure can be obtained with traditional sensors and acquiring the detail pressure field on whole bearing pad surface is still an open challenge. In this paper, a method based on thin-film sensors technique is proposed and employed to measure the pressure distribution and oil film forces of journal bearings. The measurement is conducted on a cylindrical journal bearing with two axial grooves, and ElectroMechanical Film sensor arrays are designed and laid on the surface of the bearing pads. The oil film pressure is acquired at up to 32 measurement points in total along the bearing pads in both circumference and axial directions. The pressure distribution in a wide rotation speed range is obtained successfully by using fitting algorithm. Furthermore, the oil film forces on horizon and vertical direction are obtained through the integration of the measured pressure filed. The test results prove that it is feasible to measure the oil pressure filed of journal bearings using ElectroMechanical Film piezo-film sensor array.

An Experimental Study of Static and Dynamic Characteristics of a 580mm(22.8in.) Diameter Direct Lubrication Tilting Pad Journal Bearing

2005 ◽  
Vol 128 (1) ◽  
pp. 146-154 ◽  
Author(s):  
Kazunori Ikeda ◽  
Toshio Hirano ◽  
Tatsuo Yamashita ◽  
Makoto Mikami ◽  
Hitoshi Sakakida
Keyword(s):  
Dynamic Characteristics ◽  
Large Scale ◽  
Load Capacity ◽  
Metal Temperature ◽  
Film Pressure ◽  
Static And Dynamic Characteristics ◽  
Oil Film ◽  
Analysis And Design ◽  
Tilting Pad ◽  
Oil Film Pressure

Direct lubrication tilting pad journal bearings (DLTPJ bearings) have rarely been applied to large-scale rotating machinery, such as turbines or generators, whose journal diameters are more than 500mm. In this paper, static and dynamic characteristics of a 580mm(22.8in.) diameter DLTPJ bearing were studied experimentally using a full-scale bearing test rig. In the static test, distribution of metal temperature, oil film pressure, and bearing loss were measured in changing oil flow rate, with mean bearing pressure ranging up to 2.9MPa. The maximum metal temperature of the DLTPJ bearing was compared to that of a conventional flood lubrication bearing, and it was confirmed that the direct lubrication could increase load capacity. In the dynamic test, spring and damping coefficients of oil film were obtained by exciting the bearing casing that was floated by air bellows. These data will be used for analysis and design of steam turbine rotors and their bearing systems. Also, vibration of pads was investigated because metal failure on upper pads due to vibration has been found in some actual machines. In order to generate oil film pressure on the surface of upper pads, a Rayleigh-step was machined there, and it was confirmed that vibration was reduced by the Rayleigh-step.

Static and Dynamic Characteristics of Self-Acting, Partial-Arc, Gas Journal Bearings

1964 ◽  
Vol 86 (2) ◽  
pp. 405-413 ◽  
Author(s):  
R. J. Wernick ◽  
C. H. T. Pan
Keyword(s):  
Power Series ◽  
Dynamic Characteristics ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Standard Form ◽  
Journal Bearings ◽  
Static And Dynamic Characteristics ◽  
Stability Derivatives ◽  
Bearing Loads ◽  
Gas Journal Bearing

The Reynolds equation applicable to a self-acting partial-arc gas journal bearing is perturbed in terms of the compressibility number Λ. The resulting set of equations is then put into a standard form and Galerkin’s method is used to obtain bearing loads and stability derivatives. These results are expressed in a power series in Λ.

An Experimental Study of Static and Dynamic Characteristics of a 580 mm (22.8 in.) Diameter Direct Lubrication Tilting Pad Journal Bearing

2004 ◽  
Author(s):  
K. Ikeda ◽  
T. Hirano ◽  
T. Yamashita ◽  
M. Mikami ◽  
H. Sakakida
Keyword(s):  
Dynamic Characteristics ◽  
Large Scale ◽  
Load Capacity ◽  
Metal Temperature ◽  
Film Pressure ◽  
Static And Dynamic Characteristics ◽  
Oil Film ◽  
Analysis And Design ◽  
Tilting Pad ◽  
Oil Film Pressure

Direct lubrication tilting pad journal bearings (DLTPJ bearings) have rarely been applied to large scale rotating machinery, such as turbines or generators whose journal diameters are more than 500mm. In this paper, static and dynamic characteristics of a 580mm (22.8in.) diameter DLTPJ bearing were studied experimentally using a full scale bearing test rig. In the static test, distribution of metal temperature, oil film pressure and bearing loss were measured in changing oil flow rate, with mean bearing pressure ranging up to 2.9MPa. Maximum metal temperature of DLTPJ bearing was compared to that of conventional flood lubrication bearing, and it was confirmed that the direct lubrication can increase load capacity. In the dynamic test, spring and damping coefficients of oil film were obtained by exciting the bearing casing that was floated by air bellows. These data will be used for analysis and design of steam turbine rotors and their bearing systems. Also, vibration of pads was investigated, because metal failure on upper pads due to vibration has been found in some actual machines. In order to generate oil film pressure on the surface of upper pads, Rayleigh-Step was machined there. And it was confirmed that vibration was reduced by Rayleigh-step.

Thermal Deformation of Pads in Tilting 5-Pad Journal Bearing

2005 ◽  
Author(s):  
S. Strzelecki ◽  
L. Kusmierz ◽  
G. Poniewaz
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Oil Film ◽  
Tilting Pad ◽  
Drive Trains ◽  
Shaft Misalignment ◽  
Tilting Pad Journal Bearings ◽  
Turbine Drive ◽  
Oil Film Pressure

In high speed compressors and turbine drive trains, the tilting 5-pad journal bearings are applied. Tilting-pad journal bearings are good option because they have very good hydrodynamic stability at high speed and are less sensitive to load direction and shaft misalignment. The paper introduces thermo-elastic deformations of tilting 3-pad journal bearing with asymmetric support of pads and operating at the conditions of adiabatic oil film. The deformations of pads were obtained based on the oil film pressure and temperature distributions. Reynolds, energy, geometry and viscosity equations have been solved numerically on the assumption of aligned orientation of bearing and journal axis and at static equilibrium position of journal.

Static and Dynamic Characteristics of Rolling-Pad Journal Bearings in Super-Laminar Flow Regime

1988 ◽  
Vol 110 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Makoto Mikami ◽  
Mikio Kumagai ◽  
Shuetsu Uno ◽  
Hiromu Hashimoto
Keyword(s):  
Friction Force ◽  
Dynamic Characteristics ◽  
Load Capacity ◽  
Journal Bearings ◽  
Curvature Radius ◽  
Static And Dynamic Characteristics ◽  
Oil Film ◽  
Lubrication Equation ◽  
Viscous Heat ◽  
Before And After

Static and dynamic characteristics of load-on-type rolling-pad journal bearings with six pads have been studied theoretically and experimentally by considering the effects of both turbulence and viscous heat generation in the oil film. By concurrently solving a turbulent lubrication equation and an adiabatic energy equation, pressure and temperature distributions, load capacity, and friction force are obtained. Moreover, the linearlized spring and damping coefficients of oil film are calculated under the assumption of small displacements of the journal center. It is found that the load capacity and the friction force considerably increase due to turbulence, and the effects of heat generated under turbulent conditions are more pronounced than those under laminar conditions. Also clarified are that bearing characteristics are improved by preloading the lower-side two pads located before and after the lowest pad, and that the curvature radius of the pad insignificantly affects the characteristics. The experimental results on static characteristics agree well with the theoretical results.

An Experimental Study of Journal Bearing Lubrication Effected by Journal Misalignment as a Result of Shaft Deformation Under Load

2005 ◽  
Vol 127 (4) ◽  
pp. 813-819 ◽  
Author(s):  
Jun Sun ◽  
Changlin Gui ◽  
Zhiyuan Li
Keyword(s):  
Journal Bearing ◽  
Friction Pair ◽  
Obvious Effect ◽  
Oil Film ◽  
Lubrication Performance ◽  
Mechanical Devices ◽  
Journal Misalignment ◽  
Shaft Deformation ◽  
Oil Film Pressure ◽  
Bearing Friction

Journal bearing friction pair system is one of the most general and essential parts used in various mechanical devices. A special test bench is developed for the study on lubrication performance of cylindrical journal bearings. The effect of journal misalignment as a result of shaft bending under load is studied. The results show obvious changes at distribution and value of oil film pressure, oil film thickness and oil temperature of journal bearing due to journal misalignment. The higher the load on the shaft, the larger the journal misalignment resulted from shaft deformation, the more obvious effect on lubrication performance of journal bearing.

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