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 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.

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.

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.

Misalignment Effect on the Static and Dynamic Characteristics of Hydrodynamic Journal Bearings

1995 ◽  
Vol 117 (4) ◽  
pp. 717-723 ◽  
Author(s):  
Z. L Qiu ◽  
A. K. Tieu
Keyword(s):  
Dynamic Characteristics ◽  
Reynolds Equation ◽  
Static Load ◽  
Load Capacity ◽  
Vertical Direction ◽  
Journal Bearings ◽  
Static And Dynamic Characteristics ◽  
Flow Friction ◽  
The Stability ◽  
Side Flow

This paper solves the Reynolds equation by the finite difference method in a fixed coordinate system with the static load acted in the vertical direction. All static and dynamic characteristics (including load capacity, attitude angle, side flow, friction force, misaligned moments, and eight linear force coefficients) of a horizontally grooved bearing under different eccentricity and misalignment conditions are presented and compared with available experimental data. The effects of misalignment on all these bearing characteristics and on the stability of the rotor-bearing system are analyzed.

Static and dynamic characteristics and stability analysis of high-speed water-lubricated hydrodynamic journal bearings

2021 ◽  
pp. 135065012110270
Author(s):  
Bo Xu ◽  
Hun Guo ◽  
Xiaofeng Wu ◽  
Yafeng He ◽  
Xiangzhi Wang ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Load Capacity ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Inertia Effect ◽  
Static And Dynamic Characteristics ◽  
Damping Coefficients ◽  
Stiffness And Damping

The purpose of this paper is to analyze the influence of turbulent, inertia, and misaligned effects on the static and dynamic characteristics and stability of high-speed water-lubricated hydrodynamic journal bearings. Based on the Navier–Stokes equation, the mixing-length theory, and the essential assumption that the velocity profile is not strongly affected by inertia force, the fluid lubrication model with turbulent, inertia, and misaligned effects is established, and then the stability analysis of bearings is carried out based on the equation of motion with four degrees of freedom. The model is solved by the finite difference method and the numerical results are compared under different operating conditions. The results show that the turbulent effect greatly increases the load capacity, power consumption, stiffness and damping coefficients, and stability of bearings, and the inertia effect significantly increases the volume flow rate of bearings, and the misaligned effect increases the load capacity, stiffness and damping coefficients, and stability of bearings. In high rotary speed and moderate eccentricity ratios, the influence of the inertia effect on the load capacity, stiffness coefficients, and stability cannot be neglected.

Analysis of static and dynamic characteristics of spiral-grooved gas journal bearings in high speed

2019 ◽  
Vol 233 (19-20) ◽  
pp. 6774-6792 ◽  
Author(s):  
Laiyun Song ◽  
Kai Cheng ◽  
Hui Ding ◽  
Shijin Chen ◽  
Qiang Gao
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Load Capacity ◽  
Structural Parameters ◽  
Dynamic Stiffness ◽  
Journal Bearings ◽  
Linear Perturbation ◽  
Static And Dynamic Characteristics ◽  
Gas Bearings ◽  
Spiral Grooves

The spiral grooves structures could promote load capacity and improve stability of the gas journal bearings working in high-speed condition. In this study, the unsteady Reynolds equation is solved by linear perturbation method and finite difference method in which the mesh of the groove region is specially treated. The static and dynamic characteristics of spiral grooves journal gas bearings are investigated in different working conditions and the pumping effect caused by spiral-groove structure is revealed and analyzed. Further, the influences of groove structural parameters on the dynamic stiffness and damping coefficients are studied and discussed, which provides guidelines for the design of the journal gas bearings with spiral grooves.

scholarly journals Dynamic Characteristics of the Oil Film in Journal Bearings

1982 ◽  
Vol 1982 (151) ◽  
pp. 292-298 ◽  
Author(s):  
Yoshiyuki Yamamoto ◽  
Hideomi Ohtsubo ◽  
Shin Morishita
Keyword(s):  
Dynamic Characteristics ◽  
Journal Bearings ◽  
Oil Film
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