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.

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.

Performance Analysis of High Speed Floating Ring Hybrid Bearing in the Laminar and Turbulent Regimes

2011 ◽  
Vol 197-198 ◽  
pp. 1776-1780 ◽  
Author(s):  
Hong Guo ◽  
Bo Qian Xia ◽  
Shao Qi Cen
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Turbulent Flow ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Load Capacity ◽  
Flow Equation ◽  
The Finite Element Method ◽  
Static And Dynamic Characteristics ◽  
Hybrid Bearing

This paper presents a theoretical study concerning the static and dynamic characteristics of high speed journal floating ring hybrid bearing compensated by interior restrictor under laminar flow and turbulent flow respectively. The turbulent flow fluid film control equations and the pressure boundary conditions of this floating ring bearing together with the restrictor flow equation are solved by using the Finite Element Method. The variation regularity of static and dynamic characteristics such as load capacity, friction power loss, stiffness, damping etc. is analyzed. By comparing the laminar flow results and turbulent flow results, it is found that the characteristics coefficients are adjacent under small Reynolds number (laminar flow is dominant). But the characteristics coefficients are discrepant under big Reynolds number (turbulent flow is dominant). So turbulence lubrication theory is more accurate to high speed floating ring bearing.

scholarly journals Mathematical Model and Analysis of the Water-Lubricated Hydrostatic Journal Bearings considering the Translational and Tilting Motions

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Hui-Hui Feng ◽  
Chun-Dong Xu ◽  
Jie Wan
Keyword(s):  
High Speed ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Journal Bearings ◽  
Linear Perturbation ◽  
Eccentricity Ratio ◽  
Dynamic Coefficients ◽  
Pressure Fields ◽  
Dynamic Performances ◽  
Rotary Speed

The water-lubricated bearings have been paid attention for their advantages to reduce the power loss and temperature rise and increase load capacity at high speed. To fully study the complete dynamic coefficients of two water-lubricated, hydrostatic journal bearings used to support a rigid rotor, a four-degree-of-freedom model considering the translational and tilting motion is presented. The effects of tilting ratio, rotary speed, and eccentricity ratio on the static and dynamic performances of the bearings are investigated. The bulk turbulent Reynolds equation is adopted. The finite difference method and a linear perturbation method are used to calculate the zeroth- and first-order pressure fields to obtain the static and dynamic coefficients. The results suggest that when the tilting ratio is smaller than 0.4 or the eccentricity ratio is smaller than 0.1, the static and dynamic characteristics are relatively insensitive to the tilting and eccentricity ratios; however, for larger tilting or eccentricity ratios, the tilting and eccentric effects should be fully considered. Meanwhile, the rotary speed significantly affects the performance of the hydrostatic, water-lubricated bearings.

Adiabatic Approximate Solution for Static and Dynamic Characteristics of Turbulent Partial Journal Bearings With Surface Roughness

1994 ◽  
Vol 116 (4) ◽  
pp. 672-680 ◽  
Author(s):  
H. Hashimoto ◽  
M. Mongkolwongrojn
Keyword(s):  
Surface Roughness ◽  
Approximate Solution ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Journal Bearings ◽  
Numerical Results ◽  
Operating Conditions ◽  
Finite Width ◽  
Homogeneous Surface ◽  
Static And Dynamic Characteristics

Hydrodynamic bearings are generally used for a long term, so the bearing surfaces may be roughened for many reasons such as wear, impulsive damage, foreign particles, cavitation erosion, rust, and so on. Under the turbulent operating conditions of high speed bearings, the surface roughness may result in considerable increase in both film pressure and temperature. This paper describes an adiabatic approximate solution for the static and dynamic characteristics of 180 deg partial journal bearings with homogeneous surface roughness. Applying the modified lubrication equation and energy equation, considering the combined effects of turbulence and surface roughness, to the finite width 180 deg partial journal bearings, the static and dynamic characteristics such as pressure and temperature distributions, Sommerfeld number, attitude angle, spring and damping coefficients and whirl onset velocity are obtained numerically. In the numerical analysis of the temperature distribution, adiabatic boundary conditions are assumed and then the heat transfer effect to the journal and bearing-bush surfaces is omitted. The numerical results are indicated in graphic form for various relative roughness under the mean Reynolds number of Re = 5000 and 10,000. Moreover, some numerical results of static characteristics are compared with the experimental results.

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.

Static and Dynamic Characteristics of Externally Pressurized Porous Gas Journal Bearing With Four Degrees-of-Freedom

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Shuyun Jiang ◽  
Shengye Lin ◽  
Chundong Xu
Keyword(s):  
Dynamic Characteristics ◽  
Degrees Of Freedom ◽  
Reynolds Equation ◽  
Static Load ◽  
Journal Bearing ◽  
Load Capacity ◽  
Linear Perturbation ◽  
Static And Dynamic Characteristics ◽  
Bearing Number ◽  
Gas Journal Bearing

This paper studies the static and dynamic coefficients of an externally pressurized porous gas journal bearing. The finite difference method is used to solve the Reynolds equation of the bearing to obtain the static load capacity. The linear perturbation method is adopted to derive the perturbation equations considering four degrees-of-freedom (4DOF), namely, the translational movements in x and y directions and the rotational movements around x and y directions. The effects of various parameters on the dynamic behaviors of the journal bearing are studied. These parameters include the bearing number, the supply pressure, the feeding parameter, the length-to-diameter ratio, the porosity parameter, the eccentricity ratio, and tilting angles. Simulated results prove that the proposed method is valid in estimating the static and dynamic characteristics of a porous gas journal bearing with 4DOF.

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.

Modeling and Identification of Gas Journal Bearings: Self-Acting Gas Bearing Results

2002 ◽  
Vol 124 (4) ◽  
pp. 716-724 ◽  
Author(s):  
G. Belforte ◽  
T. Raparelli ◽  
V. Viktorov
Keyword(s):  
Mathematical Model ◽  
Dynamic Characteristics ◽  
Transfer Functions ◽  
Analytical Data ◽  
Journal Bearings ◽  
Rotating Shaft ◽  
Static And Dynamic Characteristics ◽  
Gas Bearings ◽  
Wide Range ◽  
Analytical Relations

A mathematical model is elaborated with analytical relations for transfer functions and for gas-film stiffness and damping coefficients for self-acting and externally pressurized gas journal bearings with four supply orifices positioned at the center plane for rotating shaft displacements near the bearing center. Averaging and corrective coefficients are elaborated. In this paper static and dynamic characteristics of self-acting gas bearings are investigated. Results derived using the developed mathematical model are compared with the results derived from numerical computations of a non-linear distributed parameter model of the gas bearings. The results obtained demonstrate that analytical data are in good agreement with the numerical data for wide range of parameters and the mathematical model developed makes the simple calculation of static and dynamic characteristics of self-acting gas bearings possible. Derived analytical relations for transfer functions and for gas-film coefficients of gas bearings provide an efficient means for designing rotor-bearing systems.

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