Theoretical Evaluation of Capacitance, Capacitive Reactance, Resistance and Their Effects on Performance of Hydrodynamic Journal Bearings

1991 ◽  
Vol 113 (4) ◽  
pp. 762-767 ◽  
Author(s):  
H. Prashad
Keyword(s):  
Journal Bearings ◽  
Design Parameters ◽  
Clearance Ratio ◽  
Theoretical Evaluation ◽  
Active Resistance ◽  
Variable Resistor ◽  
Load Carrying ◽  
Capacitive Reactance ◽  
Bearing Design ◽  
Safe Load

A theoretical approach is developed to determine capacitance, capacitive reactance, active resistance, and impedance of hydrodynamic journal bearings under different conditions of operation. It has been established that the bearing capacitance increases with eccentricity and L/D ratios but reduces with increase in clearance ratio. On the contrary, resistance and capacitive reactance of a bearing increase with the clearance ratio but reduce with increase in the eccentricity and L/D ratios. However, the bearing impedance is more affected by the resistance than the capacitive reactance. The bearing behaves like a capacitor till the ratio of capacitive reactance to active resistance is less than unity, and acts like a variable resistor as this ratio exceeds unity. This analysis has a potential to analysis safe load carrying capacity at different speeds of operation by determining the bearing capacitance. Also, this may act as a guide to select the bearing design parameters for safe and reliable operation of a hydrodynamic journal bearing.

Theoretical Analysis of Externally Pressurized Air Journal Bearing

1970 ◽  
Vol 12 (2) ◽  
pp. 123-129 ◽  
Author(s):  
B. C. Majumdar
Keyword(s):  
Experimental Data ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Dimensional Parameters ◽  
Bearing Design

A theoretical investigation is made to predict the performance of an externally pressurized air journal bearing having several pressure sources. The pressure distribution, which leads to the determination of load-carrying capacity and flow requirement, is obtained by solving Reynolds equation numerically. The load and flow, expressed in non-dimensional parameters, are presented for different bearing design parameters (dimensionless). The results predicted by this method are compared with others' experimental data.

scholarly journals Dynamic Carrying Capacity Analysis of Double-Row Four-Point Contact Ball Slewing Bearing

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yunfeng Li ◽  
Di Jiang
Keyword(s):  
Dynamic Load ◽  
Carrying Capacity ◽  
Point Contact ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Double Row ◽  
Slewing Bearing ◽  
Load Carrying ◽  
Bearing Design ◽  
Capacity Surface

Carrying capacity is the most important performance index for slewing bearings. Maximizing the carrying capacity of slewing bearing is one pursuing goal for the bearing designer; this is usually realized by optimizing the design parameters. A method of analyzing the carrying capacity of double-row four-point contact ball slewing bearing by using dynamic carrying capacity surfaces was proposed in this paper. Based on the dynamic load carrying capacity surface of the slewing bearing, the effect of changes of the bearing design parameters, such as axial clearance, raceway groove radius coefficient, and contact angle, on the dynamic carrying capacity of the slewing bearing was researched; the trend and the degree of the effect of the micro changes of the bearing design parameters on the dynamic load carrying capacity of the bearing were discussed, and the results provide the basis for optimizing the design parameter of this type of slewing bearing.

scholarly journals Design and Parameter Study of a Self-Compensating Hydrostatic Rotary Bearing

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Xiaobo Zuo ◽  
Shengyi Li ◽  
Ziqiang Yin ◽  
Jianmin Wang
Keyword(s):  
Influence Factors ◽  
Resistance Ratio ◽  
Design Parameters ◽  
Parameter Study ◽  
Load Carrying Capacity ◽  
Clearance Ratio ◽  
Load Carrying ◽  
Static Performance ◽  
Initial Clearance ◽  
Flow Conservation

The influence of design parameters on the static performance of a newly designed self-compensating hydrostatic rotary bearing was investigated. The bearing was designed by incorporating the main attributes of angled-surface self-compensating bearing and opposed-pad self-compensating bearing. A governing model based on flow conservation was built to theoretically study the static performance, and the methodology was validated by experiments. It is pointed out that the influence factors on the bearing static performance are the designed resistance ratio of the restricting land to the bearing land, the inner resistance ratio of the land between pockets to that between the pocket and the drain groove, the initial clearance ratio of the restricting gap to the bearing gap, and the semiconical angle. Their effects on the load carrying capacity and stiffness were investigated by simulation. Results show that the optimum designed resistance ratio is 1; the initial clearance ratio should be small, and the inner resistance ratio should be large.

Optimization of circular hydrostatic axial journal bearings using a multicriteria approach

2003 ◽  
Vol 217 (3) ◽  
pp. 235-241 ◽  
Author(s):  
E Solmaz ◽  
F C Babalik ◽  
F Öztürk
Keyword(s):  
Design Process ◽  
Temperature Rise ◽  
Multicriteria Optimization ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Design Parameters ◽  
Optimization Approach ◽  
Power Requirement ◽  
Research Outcomes ◽  
Bearing Design

The solutions that best optimize the design process must be determined using single-criterion and multicriteria approaches. In this research, a multicriteria optimization approach is carried out to determine the circular hydrostatic journal bearing design parameters based on the power requirement, the bearing coefficient and the minimization of the temperature rise of the oil, so that the total performance of the system is optimal. The optimization results of more than two criteria are presented and compared with previous research outcomes. Computational experimental results are given to demonstrate the effectiveness of the present approach.

Externally-Pressurized Gas-Lubricated Floating-Ring Porous Journal Bearings: Part 1: Steady State Analysis

1984 ◽  
Vol 198 (4) ◽  
pp. 213-224 ◽  
Author(s):  
M Malik
Keyword(s):  
Steady State ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Design Parameters ◽  
Fixed Bearing ◽  
Steady State Analysis ◽  
Permeability Parameter ◽  
New Type ◽  
Bearing Design ◽  
Steady State Performance

A new type of gas-lubricated floating-ring journal bearing in which the fixed bearing and the ring are both porous, has been conceived and analysed, theoretically, for the steady state characteristics. Bearing characteristics are presented against two design parameters, namely, clearances ratio and permeability parameter. The comparison of these characteristics with those of externally-pressurized plain porous journal bearings shows that the new bearing represents, with its steady state performance, a distinctly advanced bearing design.

Journal Vibration: Influence of Compliant Bearing Design

2012 ◽  
Author(s):  
Matthew Cha ◽  
Sergei Glavatskih
Keyword(s):  
Dynamic Response ◽  
Nonlinear Dynamic ◽  
Dynamic Behaviour ◽  
Journal Bearings ◽  
Design Parameters ◽  
Radial Clearance ◽  
White Metal ◽  
Tilting Pad ◽  
Bearing Design ◽  
Tilting Pad Journal Bearings

In this paper, the nonlinear dynamic behaviour of vertical and horizontal rotors in compliant tilting pad journal bearings has been investigated. White metal and compliant bearings with line pivot pads are compared. The dynamic response of four pad bearings with different preload factors is studied. The effect of viscoelasticity is also considered in comparison with purely elastic compliant and white metal liners. The influence of radial clearance and pad offset is analysed. It is shown how pad design parameters such as preload factor, pivot offset, viscoelasticity of the liner, and radial clearance can be selected to control the size of the journal orbit in compliant bearings.

Load Carrying Efficiency of Floating Ring Journal Bearings

1983 ◽  
Vol 105 (4) ◽  
pp. 605-607 ◽  
Author(s):  
D. F. Wilcock
Keyword(s):  
External Load ◽  
Power Loss ◽  
Full Range ◽  
Journal Bearings ◽  
Length Ratio ◽  
Eccentricity Ratio ◽  
Clearance Ratio ◽  
Isothermal Conditions ◽  
Load Carrying

Floating ring bearings are compared to single film journal bearings over the full range from laminar to turbulent conditions in the films. Isothermal conditions are assumed. Assuming each type carries the same external load and operates at the same eccentricity ratio as determined by the Capacity Number, reductions in the power loss required range from 31 to 64 percent when the clearance ratio C0/(C1 + C2) is held constant and the length is shortened, and from 42 to 63 percent when the length ratio L0/L is held constant and the clearance ratio C0/(C1 + C2) is reduced. Equilibrium ring speeds range from ω0/3 to 0.45 ω0.

Bearing Performance Limits With Grease Lubrication

2005 ◽  
Author(s):  
P. M. Cann ◽  
A. A. Lubrecht
Keyword(s):  
Surface Damage ◽  
Design Parameters ◽  
Performance Limits ◽  
Grease Lubrication ◽  
Lubricated Contacts ◽  
System A ◽  
Operating Limits ◽  
Bearing Design ◽  
Cage Effects ◽  
Efficient Mechanisms

This paper has examined the influence of bearing design and operation in controlling lubricant supply to the contact zone. Grease lubricated contacts are liable to starvation and as a result the film thickness is reduced, this can result in surface damage or premature bearing failure. It is of obvious importance to know when starvation occurs and the effect of grease type, bearing design and operation on lubrication replenishment. The aim therefore is to develop a starvation parameter capable of predicting the operating limits for a particular bearing/grease system. A number of bearing design parameters are examined in the paper, these include cage design, ball spin and bearing size. Ball spin and cage effects can be efficient mechanisms for maintaining the lubricant supply to the track. Increased bearing size, line contact geometries and high load result in reduced lubricant replenishment of the contact. Using this analysis it will be possible to establish operating limits for families of bearings.

scholarly journals Misalignment in Gas Foil Journal Bearings: An Experimental Study

2008 ◽  
Author(s):  
Samuel A. Howard
Keyword(s):  
Journal Bearings ◽  
System Level ◽  
Design Parameters ◽  
Foil Bearing ◽  
Alignment System ◽  
Successful Design ◽  
Shaft Alignment ◽  
Bearing Force ◽  
Management Schemes ◽  
Level Performance

As gas foil journal bearings become more prevalent in production machines, such as small gas turbine propulsion systems and microturbines, system level performance issues must be identified and quantified in order to provide for successful design practices. Several examples of system level design parameters that are not fully understood in foil bearing systems are thermal management schemes, alignment requirements, balance requirements, thrust load balancing, and others. In order to address some of these deficiencies and begin to develop guidelines, this paper presents a preliminary experimental investigation of the misalignment tolerance of gas foil journal bearing systems. Using a notional gas foil bearing supported rotor and a laser-based shaft alignment system, increasing levels of misalignment are imparted to the bearing supports while monitoring temperature at the bearing edges. The amount of misalignment that induces bearing failure is identified and compared to other conventional bearing types such as cylindrical roller bearings and angular contact ball bearings. Additionally, the dynamic response of the rotor indicates that the gas foil bearing force coefficients may be affected by misalignment.

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