Lubrication of Porous Journal Bearings

1972 ◽  
Vol 94 (1) ◽  
pp. 69-73 ◽  
Author(s):  
C. Cusano
Keyword(s):  
Analytical Solution ◽  
Coefficient Of Friction ◽  
Load Capacity ◽  
Journal Bearings ◽  
Performance Characteristics ◽  
Eccentricity Ratio ◽  
Design Variables

An analytical solution for the performance characteristics of finite porous journal bearings is obtained. Results are presented which relate the eccentricity ratio and coefficient of friction as functions of load number for design variables of 0.0001, 0.001, 0.01, and 0.1. The load capacity obtained by using the finite bearing theory is compared to the load capacity obtained by using the short-bearing approximation and the infinite-bearing approximation.

Lubrication of a Two-Layer Porous Journal Bearing

1972 ◽  
Vol 14 (5) ◽  
pp. 335-339 ◽  
Author(s):  
C. Cusano
Keyword(s):  
Analytical Solution ◽  
Coefficient Of Friction ◽  
Outer Layer ◽  
Journal Bearing ◽  
Performance Characteristics ◽  
Eccentricity Ratio ◽  
Porous Bearing ◽  
Design Variables

An analytical solution for the performance characteristics of a two-layer porous bearing, using the short-bearing approximation, is obtained. Results are presented which relate the eccentricity ratio and coefficient of friction as functions of load number for design variables of 0·0001, 0·001, 0·01, and 0·1 and for a ratio of the permeability of the outer layer to the inner layer of 20. A comparison is made between the performance of two-layer and conventional porous bearings.

Partial Slip Texture Slider and Journal Bearing Lubricated With Newtonian Fluids: A Review

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
A. Senatore ◽  
T. V. V. L. N. Rao
Keyword(s):  
Coefficient Of Friction ◽  
Surface Texture ◽  
Journal Bearing ◽  
Slip Surface ◽  
Load Capacity ◽  
Journal Bearings ◽  
Newtonian Fluids ◽  
Performance Characteristics ◽  
Partial Slip ◽  
Texture Properties

Partial slip texture surfaces have proven to be effective to improve load capacity and reduce coefficient of friction in slider and journal bearings. By controlling the partial slip surface texture properties, bearing with desired performance can be designed. It is of consequent interest to study the lubrication of slider and journal bearing systems taking into consideration design of partial slip texture surfaces. This paper aims at covering several investigation works related to slider and journal bearing lubricated with Newtonian fluids focusing on partial slip texture influence on bearing performance characteristics.

Influence of different flow regimes on the performance characteristics of a four-pad hydrostatic squeeze film damper loaded between pads

2019 ◽  
Vol 71 (3) ◽  
pp. 440-446
Author(s):  
Amina Nemchi ◽  
Ahmed Bouzidane ◽  
Aboubakeur Benariba ◽  
Hicham Aboshighiba
Keyword(s):  
Turbulent Flow ◽  
Load Capacity ◽  
Flow Regimes ◽  
Performance Characteristics ◽  
Squeeze Film ◽  
Eccentricity Ratio ◽  
Flow Conditions ◽  
Content Type ◽  
Turbulent Flow Regime ◽  
Squeeze Film Dampers

Purpose The purpose of this paper is to study the influence of different flow regimes on the dynamic characteristics of four-pad hydrostatic squeeze film dampers (SFDs) loaded between pads. Design/methodology/approach A numerical model based on Constantinescu’s turbulent lubrication theory using the finite difference method has been developed and presented to study the effect of eccentricity ratio on the performance characteristics of four-pad hydrostatic SFDs under different flow regimes. Findings It was found that the influence of turbulent flow on the dimensionless damping of four-pad hydrostatic SFDs appears to be essentially controlled by the eccentricity ratio. It was also found that the laminar flow presents higher values of load capacity compared to bearings operating under turbulent flow conditions. Originality/value In fact, the results obtained show that the journal bearing performances are significantly influenced by the turbulent flow regime. The study is expected to be useful to bearing designers.

Design of Multi-Recess Hydrostatic Journal Bearings for Minimum Total Power Loss

1974 ◽  
Vol 96 (1) ◽  
pp. 226-232 ◽  
Author(s):  
C. Cusano ◽  
T. F. Conry
Keyword(s):  
Rotational Speed ◽  
Power Loss ◽  
Load Capacity ◽  
Maximum Load ◽  
Journal Bearings ◽  
Design Criterion ◽  
Total Power ◽  
Eccentricity Ratio ◽  
Constant Ratio ◽  
Design Charts

The design problem is formulated for multi-recess hydrostatic journal bearings with a design criterion of minimum total power loss. The design is subject to the constraints of constant ratio of the recess area to the total bearing area and maximum load capacity for a given recess geometry. The L/D ratio, eccentricity ratio, ratio of recess area to total bearing area, and shaft rotational speed are considered as parameters. The analysis is based on the bearing model of Raimondi and Boyd [1]. This model is generally valid for low-to-moderate speeds and a ratio of recess area-to-total bearing area of approximately 0.5 or greater. Design charts are presented for bearings having a ratio of recess area-to-total bearing area of 0.6 and employing capillary and orifice restrictors, these being the most common types of compensating elements. A design example is given to illustrate the use of the design charts.

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.

Characteristics of Externally Pressurized Journal Bearings with Membrane-Type Variable-Flow Restrictors as Compensating Elements

1974 ◽  
Vol 188 (1) ◽  
pp. 527-536 ◽  
Author(s):  
C. Cusano Ms
Keyword(s):  
Aspect Ratio ◽  
Load Capacity ◽  
Pressure Ratio ◽  
Journal Bearings ◽  
Eccentricity Ratio ◽  
Rotating Shaft ◽  
Variable Flow ◽  
Type Variable ◽  
Bearing Stiffness ◽  
Membrane Type

The characteristics of externally pressurized journal bearings with four recesses and with membrane-type variable-flow restrictors as compensating elements are analytically investigated by using the bearing model of Raimondi and Boyd. The effects of the ratio of the recess pressure at zero eccentricity to the supply pressure (pressure ratio), the eccentricity ratio, the compliance of the membrane and the shaft rotation on the lubricant flow rate, the load capacity and the stiffness of these bearings are presented for a given aspect ratio and inter-recess*** land width-to-diameter ratio. For a non-rotating shaft, it is shown that when the bearing operates at zero eccentricity there is a pressure ratio that gives an optimum bearing stiffness. This pressure ratio is a function of the aspect ratio of the bearing only. Using this pressure ratio, data for the load capacity and stiffness of the bearing are presented for an eccentricity ratio that varies from 0 to 0·1. For these data, the membrane compliances used are those that would give an infinite bearing stiffness if the bearing were operating at zero eccentricity.

On the Analytical Solution of Externally Pressurized Porous Gas Journal Bearings

1978 ◽  
Vol 100 (3) ◽  
pp. 442-444 ◽  
Author(s):  
B. C. Majumdar
Keyword(s):  
Analytical Solution ◽  
Pressure Distribution ◽  
Closed Form ◽  
Closed Form Solution ◽  
Journal Bearings ◽  
Form Solution ◽  
Performance Characteristics ◽  
Gas Bearing ◽  
Good Agreement

A closed form solution of pressure distribution which leads to the determination of bearing performance characteristics of an externally pressurized porous gas bearing without journal rotation is obtained. A good agreement with a similar available solution confirms the validity of the method.

Feasibility of Gas-Expanded Lubricants for Increased Energy Efficiency in Tilting-Pad Journal Bearings

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Andres Clarens ◽  
Amir Younan ◽  
Shibo Wang ◽  
Paul Allaire
Keyword(s):  
Supercritical Co2 ◽  
Power Loss ◽  
Load Capacity ◽  
Reducing Power ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Eccentricity Ratio ◽  
Power Losses ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearings

Lubricants are necessary in tilting-pad journal bearings to ensure separation between solid surfaces and to dissipate heat. They are also responsible for much of the undesirable power losses that can occur through a bearing. Here, a novel method to reduce power losses in tilting-pad journal bearings is proposed in which the conventional lubricant is substituted by a binary mixture of synthetic lubricant and dissolved CO2. These gas-expanded lubricants (GELs) would be delivered to a reinforced bearing housing capable of withstanding modest pressures less than 10 MPa. For bearings subject to loads that are both variable and predictable, GELs could be used to adjust lubricant properties in real time. High-pressure lubricants, mostly gases, have already been explored in tilting-pad journal bearings as a means to accommodate higher shaft speeds while reducing power losses and eliminating the potential for thermal degradation of the lubricant. These gas-lubricated bearings have intrinsic limitations in terms of bearing size and load capacity. The proposed system would combine the loading capabilities of conventional lubricated bearings with the efficiency of gas-lubricated bearings. The liquid or supercritical CO2 serves as a low-viscosity and completely miscible additive to the lubricant that can be easily removed by purging the gas after releasing the pressure. In this way, the lubricant can be fully recycled, as in conventional systems, while controlling the lubricant properties dynamically by adding liquid or supercritical CO2. Lubricant properties of interest, such as viscosity, can be easily tuned by controlling the pressure inside the bearing housing. Experimental measurements of viscosity for mixtures of polyalkylene glycol (PAG)+CO2 at various compositions demonstrate that significant reductions in mixture viscosity can be achieved with relatively small additions of CO2. The measured parameters are used in a thermoelastohydrodynamic model of tilting-pad journal bearing performance to evaluate the bearing response to GELs. Model estimates of power loss, eccentricity ratio, and pad temperature suggest that bearings would respond quite favorably over a range of speed and preload conditions. Calculated power loss reductions of 20% are observed when compared with both a reference petroleum lubricant and PAG without CO2. Pad temperature is also maintained without significant increases in eccentricity ratio. Both power loss and pad temperature are directly correlated with PAG-CO2 composition, suggesting that these mixtures could be used as “smart” lubricants responsive to system operating conditions.

Surface Roughness and Magnetic Effect of Magnetized Journal Bearings Lubricated with Ferrofluid

2015 ◽  
Vol 642 ◽  
pp. 242-247
Author(s):  
Tze Chi Hsu ◽  
Jing Hong Chen ◽  
Tsu Liang Chou ◽  
Hsiu Lu Chiang
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
Load Capacity ◽  
Hydrodynamic Pressure ◽  
Critical Value ◽  
Journal Bearings ◽  
Diameter Ratio ◽  
Eccentricity Ratio ◽  
High Eccentricity ◽  
The Magnetic Field

This study investigated the combined influence of stochastic surface roughness patterns and a magnetic field produced by an infinitely long wire on the distribution of hydrodynamic pressure in journal bearings lubricated with ferrofluids. According to our results, the magnetic field can raise the dimensionless pressure, improve the dimensionless load capacity and reduce the modified friction coefficient, especially at high eccentricity ratio. However, these bearing Characteristics are also influenced by surface roughness pattern depend on the length to diameter ratio λ, and the critical value of λ equal to 0.6, 0.95 and 1.8 in this study.

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