A direct numerical approach to compute the nonlinear rotordynamic coefficient of the noncircular gas journal bearing
01 Apr 2018-Vol. 232, Iss: 4, pp 453-468
TL;DR: In this article, the numerical computation of the gas film damping was performed for a gas bearing and the results showed that the gas bearings are extensively used in several industrial applications to support rotating load at high speed due to their favorable characteristics.
Abstract: Gas bearings are extensively used in several industrial applications to support the rotating load at high speed due to its favorable characteristics. The numerical computation of the gas film dampi...
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TL;DR: In this article, the influence of misalignment on the dynamic coefficients of MEMS gas bearing is studied and the influence laws on 8 dynamic characteristic coefficients are discussed in detail, and the limit dynamic performances considering mis alignment and rarefaction effect are discussed.
22 citations
01 Jun 2021
TL;DR: In this article, a self-acting rigid gas journal bearing employing micro-depth pocketed surface topographies at the bore was explored for improving the static and dynamic performance of a selfacting rigid journal bearing.
Abstract: This paper presents the exploration for improving the static and dynamic performance behaviours of a self-acting rigid gas journal bearing employing some new conceived micro-depth pocketed surface topographies at the bore. The conceived micro-pockets comprise of relatively large size rectangular pocket having micro-depth at bearing bore in the converging zone followed by placing of different designs of sub-pockets at the trailing edge of the previous one in the direction of journal rotation. The form of equation achieved from Patir and Cheng’s model for the case of hydrodynamic lubrication regime and the related dynamic pressure equations have been solved using the finite volume method discretisation scheme followed by the solution of the algebraic equations using the Gauss-Seidel iterative method. The minimum film thickness, frictional force, side leakage, bearing dynamic coefficients, effective stiffness, effective damping, and critical mass parameters have been investigated with each new bore surface topography and compared with the performances of conventional aerodynamic journal bearing. Substantial improvements in both static and dynamic performances have been found with the new micro-pocketed bore surface topographies as compared to conventional one. Moreover, the established best bore design has produced significant increase (21%) in minimum film thickness, substantial reduction (12%) in coefficient of friction, and excellent improvement (170%) in the stability parameter (critical mass) as compared to the conventional case.
15 citations
Cites methods from "A direct numerical approach to comp..."
...Perturbation technique [19, 20, 25, 30, 32] and time-marching method [12, 21, 23, 27, 29, 31] have been employed by the researchers to study the performances of aerodynamic journal bearings under the dynamic state on their respective problems....
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TL;DR: A comprehensive literature review of the theoretical and experimental studies conducted on the performance behaviors of aerodynamic journal bearings (AJBs) is presented in this paper , where a summary of the review assessment and suggestions for research explorations in future have also been provided at the end.
7 citations
01 Jun 2019
TL;DR: In this article, an investigation has been performed on a rigid rotor supported by two-lobe journal bearings operating with a non-Newtonian lubricant, and the governing Reynolds equation for pressu...
Abstract: In the present work, an investigation has been performed on a rigid rotor supported by two-lobe journal bearings operating with a non-Newtonian lubricant. The governing Reynolds equation for pressu...
6 citations
TL;DR: In this article, a novel technique based on finite element formulation is suggested to compute air film stiffness and damping coefficient in aerostatic thrust bearing for different geometries of recess.
Abstract: Purpose
This study aims to analyze the dynamic performance of aerostatic thrust bearing for different geometries of recess. Different geometries of recess of equal recess area, i.e. circular, elliptical, rectangular and annular, have been considered in analysis. The work also analyzes the influence of tilt angle on the performance of thrust bearing. To compute the unknown pressure field, the Reynolds equation governing the flow of compressible lubricant (air) has been solved using finite element formulation. Further, separate finite element formulations have been carried out to compute fluid film stiffness and damping coefficients directly. This method provides quick computation of stiffness and damping coefficients of aerostatic thrust bearing than the usual approach.
Design/methodology/approach
As the Reynolds equation governing the flow of compressible lubricant is nonlinear partial differential equation, the computation of the stiffness and damping coefficient follows an iterative procedure. It requires a lot of computational energy. Therefore, in the present work, a novel technique based on finite element formulation is suggested to compute air film stiffness and damping coefficient in aerostatic thrust bearing.
Findings
A novel technique based on finite element formulation is illustrated to simulate the performance of tilted pad aerostatic thrust bearing. On the basis of simulated results, following key conclusions may be drawn. The static and dynamic performance of a circular aerostatic tilted thrust pad bearing is significantly affected with a change in the value of tilt parameter and the shape of the recess.
Research limitations/implications
Implications are as follows: direct computation of air film damping coefficient is performed without perturbation method in finite element method (FEM); influence of tilt on aerostatic thrust bearing is studied; influence of recess shape on aerostatic thrust bearing is observed; and finite element formulation of aerostatic thrust bearing is performed.
Originality/value
The present work will be quite useful for bearing designer and academicians.
5 citations
References
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TL;DR: The Euler Method and its Generalizations Analysis of Runge-Kutta Methods General Linear Methods Bibliography.
Abstract: Mathematical and Computational Introduction The Euler Method and its Generalizations Analysis of Runge-Kutta Methods General Linear Methods Bibliography.
1,313 citations
Book•
27 Sep 2007
TL;DR: This book is written as an introduction to rotor-bearing dynamics for practicing engineers and students who are involved in rotordynamics and bearing design.
Abstract: This book is written as an introduction to rotor-bearing dynamics for practicing engineers and students who are involved in rotordynamics and bearing design. The goal of this book is to In this system figure out to the path. Hunting is the question remains unanswered how opposite direction as inputs are thus. Seems strange doesn't it oscillates as therefore the decision rule. Several particular system dynamics diagramming convention, move.
138 citations
TL;DR: In this article, a theoretical study concerning the static and dynamic performance of a circular thrust pad hydrostatic bearing having recesses of different geometric shapes has been performed using the Finite Element Method.
104 citations
TL;DR: A pad assembly method for analyzing tilting-pad bearings is presented in this article, which results in the complete coefficient matrix for a tilting pad bearing; the matrix is independent of the pad inertia, the pitch frequency and the number of degrees of freedom of the bearing.
71 citations