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 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 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.

Squeeze Film Dampers: Amplitude Effects at Low Squeeze Numbers

1975 ◽  
Vol 97 (4) ◽  
pp. 1366-1370 ◽  
Author(s):  
Martin H. Sadd ◽  
A. Kent Stiffler
Keyword(s):  
Reynolds Equation ◽  
Dynamic Performance ◽  
Squeeze Film ◽  
Periodic Disturbance ◽  
Squeeze Film Dampers ◽  
Parallel Surfaces ◽  
Load Characteristics ◽  
Squeeze Number ◽  
Stiffness And Damping ◽  
Film Stiffness

Gaseous squeeze film dampers are analyzed to determine the effect of periodic disturbance amplitude on the dynamic performance. Both circular and rectangular parallel surfaces are investigated. A solution of the nonlinear Reynolds equation is obtained by expanding the pressure in powers of the squeeze number σ, retaining up to and including terms 0(σ2). The time dependent load characteristics are found. The effect of disturbance amplitude on the film stiffness and damping is given.

Dynamic Analysis of High-Speed Hybrid Thrust Bearings

2013 ◽  
Vol 365-366 ◽  
pp. 304-308
Author(s):  
Lei Wang
Keyword(s):  
Dynamic Analysis ◽  
High Speed ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Dynamic Performance ◽  
Orifice Diameter ◽  
Thrust Bearings ◽  
Supply Pressure ◽  
Bearing Stiffness ◽  
Stiffness And Damping

An analysis is conducted and solutions are provided for the dynamic performance of high speed hybrid thrust bearing. By adopting bulk flow theory, the turbulent Reynolds equation is solved numerically with the different orifice diameter and supply pressure. The results show that increasing supply pressure can significantly improve the bearing stiffness and damping, while the orifice diameters make a different effect on the bearing stiffness and damping.

scholarly journals Effect of groove texture on the dynamic characteristics of water-lubricated thrust bearing

2018 ◽  
Vol 213 ◽  
pp. 01003
Author(s):  
Huihui Feng ◽  
Liping Peng
Keyword(s):  
Dynamic Characteristics ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Water Film ◽  
Geometrical Parameters ◽  
Damping Coefficients ◽  
Rotary Speed ◽  
Stiffness And Damping ◽  
Groove Texture ◽  
Film Lubrication

In this study, the effects of groove texture on the dynamic characteristics of water-lubricated thrust bearing are theoretically investigated. The turbulent Reynolds equation and its perturbation equations for water-film lubrication are derived and solved by using finite difference method. Dynamic characteristics including the stiffness and damping coefficients of the bearing are calculated. The effects of rotary speed, film clearance and geometrical parameters including groove texture depth and circumferential angle on the dynamic characteristics of the bearing have been investigated.

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 Characteristics of Externally Pressurized Rectangular Porous Gas Thrust Bearings

1976 ◽  
Vol 98 (1) ◽  
pp. 181-186 ◽  
Author(s):  
B. C. Majumdar
Keyword(s):  
Design Procedure ◽  
Theoretical Data ◽  
Periodic Load ◽  
Small Perturbations ◽  
Thrust Bearings ◽  
Design Variables ◽  
Wide Range ◽  
Stiffness And Damping ◽  
Compressible Lubricant

A theoretical study on the behavior of an externally pressurized rectangular porous thrust bearing is made using compressible lubricant. A periodic load is imposed on the bearing and the pressure distribution which leads to the determination of stiffness and damping is obtained by small perturbations. The results are calculated numerically using a digital computer. The tabulated theoretical data of a square pad given for a wide range of design variables enable one to use directly in the design. A design procedure of such a bearing is also indicated.

scholarly journals Run-Up Simulation of a Semi-Floating Ring Supported Turbocharger Rotor Considering Thrust Bearing and Mass-Conserving Cavitation

Lubricants ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 44
Author(s):  
Christian Ziese ◽  
Cornelius Irmscher ◽  
Steffen Nitzschke ◽  
Christian Daniel ◽  
Elmar Woschke
Keyword(s):  
Reynolds Equation ◽  
Energy Equation ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Reliable Prediction ◽  
Two Phase ◽  
Hydrodynamic Bearings ◽  
Thrust Bearings ◽  
Run Up ◽  
The Impact

The vibration behaviour of turbocharger rotors is influenced by the acting loads as well as by the type and arrangement of the hydrodynamic bearings and their operating condition. Due to the highly non-linear bearing behaviour, lubricant film-induced excitations can occur, which lead to sub-synchronous rotor vibrations. A significant impact on the oscillation behaviour is attributed to the pressure distribution in the hydrodynamic bearings, which is influenced by the thermo-hydrodynamic conditions and the occurrence of outgassing processes. This contribution investigates the vibration behaviour of a floating ring supported turbocharger rotor. For detailed modelling of the bearings, the Reynolds equation with mass-conserving cavitation, the three-dimensional energy equation and the heat conduction equation are solved. To examine the impact of outgassing processes and thrust bearing on the occurrence of sub-synchronous rotor vibrations separately, a variation of the bearing model is made. This includes run-up simulations considering or neglecting thrust bearings and two-phase flow in the lubrication gap. It is shown that, for a reliable prediction of sub-synchronous vibrations, both the modelling of outgassing processes in hydrodynamic bearings and the consideration of thrust bearing are necessary.

Characteristics evaluation of gas film in the aerostatic thrust bearing within rarefied effect

2016 ◽  
Vol 231 (2) ◽  
pp. 149-157 ◽  
Author(s):  
Dongju Chen ◽  
Shuai Zhou ◽  
Jihong Han ◽  
Jinwei Fan ◽  
Qiang Cheng
Keyword(s):  
Machine Tool ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Film Flow ◽  
Machining Accuracy ◽  
Aerostatic Bearing ◽  
Supply Pressure ◽  
Slip Regime ◽  
Key Factor ◽  
Gas Supply

The characteristic of gas film is a key factor in the performance of the aerostatic bearing. Because the gas film flow is in the slip regime, influence of the rarefied effect is significant. The modified Reynolds equation suitable for compressible gas in the rarefied effect is deduced through introducing the flow factor in the rarefied effect to the Reynolds equation. Pressure distribution, capacity, and stiffness of the gas film under the rarefied effect are analyzed. With the increase of gas pressure, the gas film capacity and stiffness of bearing would also increase. However, the greater the gas supply pressure, the more intense the gas film vibration, so it was important to select a reasonable gas supply pressure for achieving the optimal gas film characteristic. Finally, the gas rarefied effect is verified by the experiment indirectly, which agreed well with the analytical results and provided a theoretical guidance for the machining accuracy of the machine tool.

Static Characteristics of Gas Foil Thrust Bearing Based on Gas Rarefaction Model

2015 ◽  
Author(s):  
Jiajia Yan ◽  
Guanghui Zhang ◽  
Zhansheng Liu ◽  
Fan Yang
Keyword(s):  
Film Thickness ◽  
Optimization Design ◽  
Reynolds Equation ◽  
Thrust Bearing ◽  
Rarefied Gas ◽  
Load Capacity ◽  
Structural Parameters ◽  
Lubricating Film ◽  
Lift Off ◽  
Foil Thrust Bearing

A modified Reynolds equation for bump type gas foil thrust bearing was established with consideration of the gas rarefaction coefficient. Under rarefied gas lubrication, the Knudsen number which was affected by the film thickness and pressure was introduced to the Reynolds equation. The coupled modified Reynolds and lubricating film thickness equations were solved using Newton-Raphson Iterative Method and Finite Difference Method. By calculating the load capacity for increasing rotor speeds, the lift-off speed under certain static load was obtained. Parametric studies for a series of structural parameters and assembled clearances were carried out for bearing optimization design. The results indicate that with gas rarefaction effect, the axial load capacity would be decreased, and the lift-off speed would be improved. The rarefied gas has a more remarkable impact under a lower rotating speed and a smaller foil compliance coefficient. When the assembled clearance of the thrust bearing rotor system lies in a small value, the lift-off speed increases dramatically as the assembled clearance decreases further. Therefore, the axial clearance should be controlled carefully in assembling the foil thrust bearing. It’s worth noting that the linear uniform bump foil stiffness model is not exact for large foil compliance ∼0.5, especially for lift-off speed analysis, due to ignoring the interaction between bumps and bending stiffness of the foil.

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