Combined Influence of Misalignment and Orifice Diameter on the Static Performances of Hydrostatic, Water-Lubricated Journal Bearings

2014 ◽  
Vol 607 ◽  
pp. 608-611
Author(s):  
Hui Hui Feng ◽  
Chun Dong Xu ◽  
Feng Feng Wang
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Film Thickness ◽  
Power Loss ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Orifice Diameter ◽  
Rigid Rotor ◽  
Static Performance

The water-lubricated bearings have gained an increasing focus to overcome the disadvantages of the oil film bearings and gas bearings. In this paper, the influences of orifice diameter in aligned and misaligned conditions on the static performance of two hydrostatic, four-recess, water-lubricated journal bearings used to support a rigid rotor, are investigated. The steady Reynolds equation for the journal bearing for the turbulent bulk flow and the film thickness expression considering tilting angles are used and numerically solved by finite difference method. Results demonstrate that the static performances, such as the quality, power loss and temperature rise are affected by the tilting angles, orifice diameter to some degree.

Analysis of Infinitely Short and Infinitely Long Hydrodynamic Journal Bearings Under Micro-Polar Fluid by Direct Integration Method

2017 ◽  
Author(s):  
Bikash Routh
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Integration Method ◽  
Pressure Profile ◽  
Journal Bearings ◽  
Direct Integration ◽  
Polar Fluid ◽  
Direct Integration Method

In the present paper Reynolds equation of lubrication under micro-polar fluid for journal bearing is solved by direct-integration method under infinitely long and infinitely short journal bearing assumptions [1]. Infinitely long-bearing and infinitely short bearing solutions are the two available approximate closed form solutions for journal bearings. In the present investigation, solution of Reynolds equation i.e. pressure profile is compared with pressure profile obtained by previously used approximate method like finite difference method (FDM). Mentionable here that any approximation method needs lots of calculation and computer programing to get the result. In the present work it has been found that direct-integration method leads the almost same result as the conventionally used complex finite difference method. CFD analysis is also presented in the present work to justify the profile obtained by direct numerical method. It has seen here that theoretical and simulation results are in good agreement to each other’s.

Analysis of Hybrid (Hydrodynamic/Hydrostatic) Journal Bearing

2013 ◽  
Vol 650 ◽  
pp. 385-390 ◽  
Author(s):  
Vijay Kumar Dwivedi ◽  
Satish Chand ◽  
K.N. Pandey
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Gas Turbines ◽  
High Speed ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Natural Boundary Condition ◽  
Dimensional Solution

The Hybrid (hydrodynamic/ hydrostatic) journal bearing system has found wide spread application in high speed rotating machines such as compressors, gas turbines, steam turbines, etc. The present studies include solution of Reynolds equation for hydrodynamic journal bearing with infinitely long approximation (ILA), infinitely short bearing approximation (ISA) and finite journal bearing approximation. Further Finite Journal bearing approximation considers two dimensional solution of Reynolds equation with natural boundary condition, which cannot be solved by analytical method. So, here the solutions for finite journal bearing have been done with finite difference method (a MATLAB® code is prepared for finite difference method) to get bearing performance parameters such as load capacity, Sommerfeld no., etc.

Study on CFD Solution Method for Static Characteristics of Hybrid Oil Film Bearing

2012 ◽  
Vol 155-156 ◽  
pp. 236-240
Author(s):  
Da Ying Li
Keyword(s):  
Boundary Condition ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Reynolds Equation ◽  
Solution Method ◽  
Fundamental Equation ◽  
Static Characteristics ◽  
Oil Film ◽  
Static Performance ◽  
Fluent Software

Reynolds equation is the fundamental equation to solve the static performance for sleeve bearings. For hydrodynamic and hydrostatic oil film bearing with three oil recesses, the specific expressions of the fluid mechanics lubrication Reynolds equation are presented. The gridding model of the bearing is proposed, the boundary condition of the bearing is set, the static characteristics are solved and the pressure distribution of the bearing is plotted by using FLUENT software. The computation results from FLUENT are considerably accordance with the computation results from finite difference method.

Numerical investigation on the static performance of aerostatic journal bearings with different pocket shapes by the finite-element method

2020 ◽  
pp. 135065012097911
Author(s):  
Xinglong Chen ◽  
James K Mills ◽  
Kai Shi ◽  
Gang Bao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Film Thickness ◽  
Journal Bearings ◽  
Orifice Diameter ◽  
Eccentricity Ratio ◽  
The Finite Element Method ◽  
Area Formula ◽  
Static Performance ◽  
Element Method

In this work, to improve the static behavior of aerostatic journal bearings, we examine the effect of pockets with different shapes, including the square, rectangular 1, rectangular 2, and circular, manufactured on the surface of the aerostatic journal bearing. The effects of the pocket shapes, pocket area [Formula: see text], eccentricity ratio ɛ, orifice diameter df, average gas film thickness h0, and misalignment angles [Formula: see text] and [Formula: see text] on the static performance are investigated using simulations. The Reynolds equation is solved by the finite-element method in this work. Simulations reveal that the pocket area [Formula: see text], eccentricity ratio ɛ, gas film thickness h0, orifice diameter df, and misalignment angles [Formula: see text] and [Formula: see text] have a significant influence on the load force F and the stiffness K. In general, rectangular 2 pocket bearings are found to perform somewhat better than bearings with other pocket shapes, with the pocket depth set to one-half of h0, when the pocket area [Formula: see text] varies from one-twelfth to one. The pocket area [Formula: see text] should be set according to the average gas film thickness h0 and the orifice diameter df to achieve a better static performance for the bearings. For bearings operated with misalignment angles [Formula: see text] and [Formula: see text], different pocket areas [Formula: see text] should be set according to the pocket shapes for the optimal design.

Theoretical Research on Aerostatic Rectangular Guideways with Finite Difference Method

2007 ◽  
Vol 339 ◽  
pp. 371-376 ◽  
Author(s):  
Xiao Feng Zhang ◽  
Bin Lin
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Film Thickness ◽  
Pressure Distribution ◽  
Difference Method ◽  
Load Capacity ◽  
Theoretical Research ◽  
Orifice Diameter ◽  
Supply Pressure ◽  
Design And Manufacture

The load capacity and stiffness of the aerostatic rectangular guideways, which apply annular orifice restrictor and porous restrictor respectively, were analyzed with finite difference method in this paper. A program for solving the pressure distribution, load capacity and stiffness is programmed with VB. The calculated results show that the rise of supply pressure is good for improving the load capacity and stiffness of guideways. The decrease of the orifice diameter in annular orifice restriction and the permeability in porous restriction is advantageous to improve the stiffness of guideways, but both the corresponding bearing clearance and load capacity decrease. In both the annular restriction and porous restriction, the best film thickness which make the stiffness maximum exists under the definite supply pressure and parameter of the restrictor. Under the same supply pressure, the load capacity and stiffness of porous restriction is higher than the orifice restriction. Meanwhile, the design and manufacture of porous restrictor is simple. The porous restrictor is the perfect restrictor of aerostatic guideways.

scholarly journals Sensibility Analysis of Design Parameters for Journal Bearings Optimization of Mass Balancing Systems

2005 ◽  
Author(s):  
L. Morais ◽  
L. A. Ferreira
Keyword(s):  
Film Thickness ◽  
Power Loss ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Radial Clearance ◽  
Maximum Pressure ◽  
Minimum Film Thickness ◽  
Mass Balancing ◽  
Sensibility Analysis ◽  
Selection Of

This work presents a sensibility analysis for the journal bearings of combustion engines mass balancing systems. Applying it, it’s possible to improve the journal bearings and avoid possible failures. This analysis consists on studying the effects of the variation of the journal bearings main parameters (radial clearance, journal bearing diameter and journal bearing length) on the journal bearings operating conditions (minimum film thickness, maximum pressure and power loss). The analysis also includes the comparison and selection of the different metallic materials that can be used in these journal bearings, as well as the selection of the lubrication system groove suitable for the journal bearings used in this kind of application. This sensibility analysis shows that: increasing the radial clearance the minimum film thickness increases, the maximum pressure remains approximately the same and the power loss decreases; increasing the journal bearing length, the minimum film thickness and power loss increase and the maximum pressure decreases; increasing the journal bearing diameter, the minimum film thickness and power loss increase and the maximum pressure decreases. At last, it’s found that the white metals (Babbitts) are considered the most advantageous and indicated materials for these journal bearings, and that the lubrication system grooves should be circumferential.

An Investigation on the Static Performance of the Non-Circular Journal Bearing Using Fourier Analysis

2018 ◽  
Author(s):  
Jiale Tian ◽  
Baisong Yang ◽  
Lie Yu ◽  
Jian Zhou
Keyword(s):  
Fourier Series ◽  
Film Thickness ◽  
Journal Bearing ◽  
Load Capacity ◽  
Harmonic Component ◽  
Mathematical Expression ◽  
Theoretical Method ◽  
Journal Bearings ◽  
Hydrodynamic Bearing ◽  
Static Performance

As one of the most important components in a rotor-bearing system, journal bearings provide proper support and damping to the rotor so that it can run both smoothly and efficiently and keep stable under different working conditions. As the rotating speed of the rotor growing faster and load getting heavier, the traditional cylinder journal bearing can no longer meet the demand of stabilizing the rotor, so different kinds of non-circular journal bearings were invented, such as elliptical bearing, multi-lobe bearing, wave bearing and etc., to provide better stability and greater load capacity. However, these kinds of non-circular bearings were mostly designed by experience of the engineers, and also the current hydrodynamic bearing design methodology still depends on empirical design. There lacks of corresponding theoretical foundation. In order to develop a theoretical method for bearing designing, an innovative analyzing approach needs to be carried out to explore the mechanism of the bearings and its performance. In this paper, a new approach is presented focusing on the profile of each bearing and their film thickness. A universal mathematical expression for different types of non-circular bearings has been put forward based on the Fourier series theory. The influence of periodic harmonics of film thickness on the static performance of non-circular bearings of finite length is studied for incompressible lubricant. The results show that the film thickness can always be expanded into a Fourier series, and the harmonic components of film pressure can be obtained by solving the Reynolds equation. Finally, the relation between the k-th order harmonic component H0,k and the corresponding static pressure component P0,k is established. This new investigation can be used to improve the non-circular bearing designing methodology with theoretical guidance.

The effect of turbulence on the performance of a two-lobe journal bearing lubricated with a couple stress fluid

2016 ◽  
Vol 68 (3) ◽  
pp. 336-340 ◽  
Author(s):  
Boualem Chetti
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Couple Stress ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Couple Stress Fluid ◽  
Turbulent Regime ◽  
Content Type ◽  
Couple Stress Fluids

Purpose This paper presents an analysis of the static characteristics of two-lobe journal bearings lubricated with couple stress fluids operating in a turbulent regime. The modified Reynolds equation for a couple stress fluids taking into consideration the effect of turbulence is solved using finite difference method. The load-carrying capacity, attitude angle, friction coefficient and side leakage are determined for various values of the couple stress parameter and Reynolds number. It is found that the couple stress fluids affect significantly on the performance of a two-lobe journal bearing in laminar and turbulent regime. Design/methodology/approach The modified Reynolds equation for a couple stress fluids taking into consideration the effect of turbulence is solved using finite difference method. Findings It is found that the couple stress fluids affect significantly on the performance of a two-lobe journal bearing in laminar and turbulent regime. Originality/value A couple stress fluid is used for lubrication of a two-lobe journal bearing in turbulent regime and laminar.

Analysis of the Dynamic Characteristics of the Aerostatic Journal Bearings

2014 ◽  
Vol 607 ◽  
pp. 600-603
Author(s):  
Chun Dong Xu ◽  
Hui Hui Feng ◽  
Feng Feng Wang
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Dynamic Characteristics ◽  
Difference Method ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Damping Coefficients ◽  
Rotation Center ◽  
The Finite Difference Method ◽  
Stiffness And Damping

This paper investigates the dynamic characteristics of the aerostatic journal bearing, the rotation center of which is not the center of the journal length. The Finite Difference Method (FDM) and the perturbation method are employed to calculate the stiffness and damping coefficients. Results show that the coupled stiffness and damping coefficients cannot be neglected due to the rotation center being not the center of the journal length. Furthermore, with the increase of the distance between the rotation center and the center of the journal length, the coupled stiffness and damping coefficients increase.

Theoretical Condition for the Cxy=Cyx Relation in Fluid Film Journal Bearings

1989 ◽  
Vol 111 (3) ◽  
pp. 426-429 ◽  
Author(s):  
T. Kato ◽  
Y. Hori
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Fluid Film ◽  
Finite Width ◽  
Damping Coefficients ◽  
Dynamic Coefficients ◽  
Cross Terms ◽  
Linear Damping ◽  
Theoretical Condition

A computer program for calculating dynamic coefficients of journal bearings is necessary in designing fluid film journal bearings and an accuracy of the program is sometimes checked by the relation that the cross terms of linear damping coefficients of journal bearings are equal to each other, namely “Cxy = Cyx”. However, the condition for this relation has not been clear. This paper shows that the relation “Cxy = Cyx” holds in any type of finite width journal bearing when these are calculated under the following condition: (I) The governing Reynolds equation is linear in pressure or regarded as linear in numerical calculations; (II) Film thickness is given by h = c (1 + κcosθ); and (III) Boundary condition is homogeneous such as p=0 or dp/dn=0, where n denotes a normal to the boundary.

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