Analysis of the Stiffness and Damping Characteristics of an Externally Pressurized Porous Gas Journal Bearing

1977 ◽  
Vol 99 (2) ◽  
pp. 295-301 ◽  
Author(s):  
N. S. Rao
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Dynamic Pressure ◽  
Porous Wall ◽  
Small Perturbations ◽  
One Dimensional ◽  
Damping Characteristics ◽  
Flow Through ◽  
Stiffness And Damping ◽  
Gas Journal Bearing

The dynamic behavior of an externally pressurized porous gas journal bearing is analyzed by assuming one dimensional flow through porous wall. A periodic (displacement) disturbance is imposed on the bearing, and the dynamic pressure distribution is determined by small perturbations of the Reynolds equation. Stiffness and damping for various design conditions are calculated numerically using a digital computer and presented in the form of design charts and tables.

Dynamic Characteristics of an Inherently Compensated, Square, Gas Film Bearing

1975 ◽  
Vol 97 (1) ◽  
pp. 52-62 ◽  
Author(s):  
A. K. Stiffler ◽  
D. M. Smith
Keyword(s):  
Numerical Methods ◽  
Design Methodology ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Dynamic Pressure ◽  
External Pressure ◽  
Periodic Load ◽  
Small Perturbations ◽  
Squeeze Number ◽  
Stiffness And Damping

A rectangular gas film bearing with inherently compensated feedholes evenly distributed around the interior is analyzed. The feedhole boundary between the enclosed central region and the exterior perimeter region is modeled as a line source. A periodic load disturbance is imposed on the externally pressurized bearing, and the dynamic pressure distribution is determined by small perturbations of the Reynolds’ equation. The solution for the square bearing is obtained by numerical methods. Design curves are presented for the load capacity, mass flow, stiffness, and damping as a function of squeeze number, external pressure, restrictor coefficient, and source location. A design methodology is presented.

Analysis of the Stiffness and Damping of an Inherently Compensated, Multiple-Inlet, Circular Thrust Bearing

1974 ◽  
Vol 96 (3) ◽  
pp. 329-336 ◽  
Author(s):  
A. K. Stiffler
Keyword(s):  
Reynolds Equation ◽  
Thrust Bearing ◽  
Dynamic Pressure ◽  
External Pressure ◽  
Periodic Load ◽  
Small Perturbations ◽  
Central Disk ◽  
Squeeze Number ◽  
Stiffness And Damping ◽  
Disk Region

A circular thrust bearing with inherently compensated feedholes evenly distributed around an interior radius is analyzed. The feedhole boundary between the central disk region and exterior annular region is modeled as a line source. A periodic load disturbance is imposed on the bearing, and the dynamic pressure distribution is determined by small perturbations of the Reynolds equation. The solution is given in terms of Kelvin functions. Design curves are presented for the stiffness and damping as a function of squeeze number, external pressure, restrictor coefficient and feedhole location.

Dynamic Stiffness and Damping Coefficients of Aerostatic, Porous, Journal Bearings

1978 ◽  
Vol 20 (5) ◽  
pp. 291-296 ◽  
Author(s):  
N. S. Rao ◽  
B. C. Majumdar
Keyword(s):  
Continuity Equation ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Dynamic Pressure ◽  
Dynamic Stiffness ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Damping Coefficients ◽  
Design Charts ◽  
Stiffness And Damping

A periodic (displacement) disturbance is imposed on an aerostatic, porous, journal bearing of finite length under steady-state conditions. The dynamic pressure distribution is obtained by a pressure perturbation analysis of Reynolds equation and a modified flow continuity equation in a porous medium. Dynamic stiffness and damping coefficients for different operating conditions are calculated numerically, using a digital computer, and presented in the form of design charts.

Dynamic Characteristic of Multirecess Externally Pressurized Oil Journal Bearing

1978 ◽  
Vol 100 (4) ◽  
pp. 467-471 ◽  
Author(s):  
M. K. Ghosh
Keyword(s):  
Perturbation Theory ◽  
Theoretical Analysis ◽  
Dynamic Characteristic ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Harmonic Vibrations ◽  
Damping Characteristics ◽  
Stiffness And Damping ◽  
Generalized Reynolds Equation

This paper describes a theoretical analysis of the dynamic behavior of multirecess externally pressurized oil journal bearings for a nonrotating journal subjected to plane harmonic vibrations. The generalized Reynolds’ equation for a finite bearing has been solved using perturbation theory. Stiffness and damping characteristics of a capillary compensated bearing are given.

scholarly journals Dynamic Stiffness and Damping Characteristics of a High-Temperature Air Foil Journal Bearing

2001 ◽  
Vol 44 (4) ◽  
pp. 657-663 ◽  
Author(s):  
Samuela Howard ◽  
Christopher Dellacorte ◽  
Mark J. Valco ◽  
Joseph M. Prahl ◽  
Hooshang Heshmat
Keyword(s):  
High Temperature ◽  
Journal Bearing ◽  
Dynamic Stiffness ◽  
Damping Characteristics ◽  
Stiffness And Damping

Dynamic Reynolds equation for micropolar fluids and the analysis of plane inclined slider bearings with squeezing effect

2007 ◽  
Vol 221 (7) ◽  
pp. 823-829 ◽  
Author(s):  
N. B. Naduvinamani ◽  
G. B. Marali
Keyword(s):  
Reynolds Equation ◽  
Coupling Parameter ◽  
Dynamic Stiffness ◽  
Closed Form Solution ◽  
Form Solution ◽  
Squeezing Effect ◽  
Micropolar Fluids ◽  
Slider Bearings ◽  
Damping Characteristics ◽  
Stiffness And Damping

The general dynamic Reynolds equation of sliding-squeezing surfaces with micro-polar fluids is derived for the assessment of dynamic characteristics of bearings with general film thickness. The detailed analysis is presented for the plane inclined slider bearings by using perturbation method. Two Reynolds-type equations corresponding to steady performance and perturbed characteristics are obtained. The closed form solution of these equations is obtained. The numerical computations of the results show that, the micropolar fluids provide an improved characteristics for both steady-state and the dynamic stiffness and damping characteristics. It is found that the maximum steady-load-carrying capacity is function of coupling parameter and is achieved at smaller values of profile parameter for larger values of the coupling parameter.

scholarly journals Performance of an Orifice Compensated Two-Lobe Hole-Entry Hybrid Journal Bearing

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
J. Sharana Basavaraja ◽  
Satish C. Sharma ◽  
S. C. Jain
Keyword(s):  
External Load ◽  
Design Parameter ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Damping Coefficients ◽  
Symmetric Configuration ◽  
Flow Through ◽  
Direct Stiffness ◽  
Offset Factor ◽  
Bearing System

The work presented in this paper aims to study the performance of a two-lobe hole-entry hybrid journal bearing system compensated by orifice restrictors. The Reynolds equation governing the flow of lubricant in the clearance space between the journal and bearing together with the equation of flow through an orifice restrictor has been solved using FEM and Galerkin's method. The bearing performance characteristics results have been simulated for an orifice compensated nonrecessed two-lobe hole-entry hybrid journal bearing symmetric configuration for the various values of offset factor , restrictor design parameter , and the value of external load . Further, a comparative study of the performance of a two-lobe hole-entry hybrid journal bearing system with a circular hole-entry symmetric hybrid journal bearing system has also been carried out so that a designer has a better flexibility in choosing a suitable bearing configuration. The simulated numerical results indicate that for the two-lobe symmetric hole-entry hybrid journal bearing system with an offset factor greater than one provides 30 to 50 percent larger values of direct stiffness and direct damping coefficients as compared to a circular symmetric hole-entry hybrid journal bearing system.

Advancements in the Structural Stiffness and Damping of a Large Compliant Foil Journal Bearing: An Experimental Study

2004 ◽  
Vol 129 (1) ◽  
pp. 154-161 ◽  
Author(s):  
Mohsen Salehi ◽  
Hooshang Heshmat ◽  
James F. Walton
Keyword(s):  
Journal Bearing ◽  
Dynamic Stiffness ◽  
Operating Conditions ◽  
Test Facility ◽  
Squeeze Film ◽  
Structural Stiffness ◽  
Low Frequencies ◽  
Equivalent Viscous Damping ◽  
Damping Characteristics ◽  
Stiffness And Damping

This paper presents the results of an experimental investigation into the dynamic structural stiffness and damping characteristics of a 21.6‐cm(8.5in.)-diameter compliant surface foil journal bearing. The goal of this development was to achieve high levels of damping without the use of oil, as is used in squeeze film dampers, while maintaining a nearly constant dynamic stiffness over a range of frequencies and amplitudes of motion. In the experimental work described herein, a full compliant foil bearing was designed, fabricated, and tested. The test facility included a non-rotating journal located inside the bearing. The journal was connected to an electrodynamic shaker so that dynamic forces simulating expected operating conditions could be applied to the structurally compliant bump foil elements. Excitation test frequencies to a maximum of 400Hz at amplitudes of motion between 25.4 and 102μm were applied to the damper assembly. During testing, both compressive preload and unidirectional static loads of up to 1335 and 445N, respectively, were applied to the damper assembly. The experimental data from these tests were analyzed using both a single degree of freedom model and an energy method. These methods of data analysis are reviewed here and results are compared. Excellent agreement in results obtained from the two methods was achieved. Equivalent viscous damping coefficients as high as 1050N.s∕cm(600lbf.s∕in) were obtained at low frequencies. Dynamic stiffness was shown to be fairly constant with frequency.

Static and Dynamic Characteristics of Self-Acting, Partial-Arc, Gas Journal Bearings

1964 ◽  
Vol 86 (2) ◽  
pp. 405-413 ◽  
Author(s):  
R. J. Wernick ◽  
C. H. T. Pan
Keyword(s):  
Power Series ◽  
Dynamic Characteristics ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Standard Form ◽  
Journal Bearings ◽  
Static And Dynamic Characteristics ◽  
Stability Derivatives ◽  
Bearing Loads ◽  
Gas Journal Bearing

The Reynolds equation applicable to a self-acting partial-arc gas journal bearing is perturbed in terms of the compressibility number Λ. The resulting set of equations is then put into a standard form and Galerkin’s method is used to obtain bearing loads and stability derivatives. These results are expressed in a power series in Λ.

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