Multi-Constrained Optimization of Running Characteristics of Mechanisms Lubricated With Compressible Fluid

2004 ◽  
Vol 126 (1) ◽  
pp. 132-136 ◽  
Author(s):  
M. Jai ◽  
G. Buscaglia ◽  
I. Iordanoff
Keyword(s):  
Finite Element ◽  
Optimal Design ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Black Box ◽  
Finite Element Code ◽  
Slider Bearing ◽  
Galerkin Finite Element ◽  
Lubricated Contacts

The optimal design of gas-lubricated contacts is addressed, with emphasis on appropriate strategies for the management of constraints that usually arise from physical or manufacturing considerations. The necessary tools for evaluating the objective function (which is the load capacity in this case) and its gradient are recalled. The presentation aims at “black-box” implementations in which an optimization package is coupled with a completely independent Reynolds-equation solver. In our implementation DONLP2 is used as optimizer, while the solver is a Galerkin finite-element code. Two applications are reported: A fixed-volume planar slider bearing and a three-pad compliant journal bearing. In both cases the robustness of the approach is demonstrated and interesting aspects of the optimal gap profiles are presented.

A General Solution of Reynolds’ Equation for a Full Finite Journal Bearing

1967 ◽  
Vol 89 (2) ◽  
pp. 203-210 ◽  
Author(s):  
R. R. Donaldson
Keyword(s):  
Fourier Series ◽  
Series Solution ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Separation Of Variables ◽  
Hill Equation ◽  
Eigenvalues And Eigenvectors ◽  
General Series ◽  
Bearing Load

Reynolds’ equation for a full finite journal bearing lubricated by an incompressible fluid is solved by separation of variables to yield a general series solution. A resulting Hill equation is solved by Fourier series methods, and accurate eigenvalues and eigenvectors are calculated with a digital computer. The finite Sommerfeld problem is solved as an example, and precise values for the bearing load capacity are presented. Comparisons are made with the methods and numerical results of other authors.

Rayleigh Step Journal Bearing: Part 1—Compressible Fluid

1968 ◽  
Vol 90 (1) ◽  
pp. 271-280 ◽  
Author(s):  
B. J. Hamrock
Keyword(s):  
Compressible Fluid ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Maximum Load ◽  
Pressure Profile ◽  
Clearance Ratio ◽  
Attitude Angle ◽  
Step Parameters ◽  
Bearing Part

A linearized PH solution to the Reynolds equation was obtained while neglecting side leakage. The analysis was divided into two parts—the step and ridge regions. The pressure profile across the step and ridge region of the various pads which are placed around the journal was obtained from the linearized PH Reynolds equation. Knowing the pressure, the load components and attitude angle were calculated. The resulting equations were found to be a function of the bearing parameters (the eccentricity and compressibility number) and the step parameters (ratio of the stepped clearance to the ridge clearance, ratio of the angle extended by the ridge to the angle extended by the pad, and number of pads placed around the journal). The maximum load capacity can be determined by numerically differentiating the load with respect to the step bearing parameters while finding where the slope is zero. A series of data was run while varying the bearing parameters. The attitude angle was calculated for the various cases which were run.

Empirical Treatment of Hydrodynamic Journal Bearing Performance in the Superlaminar Regime

1970 ◽  
Vol 12 (2) ◽  
pp. 116-122 ◽  
Author(s):  
H. F. Black
Keyword(s):  
Reynolds Number ◽  
Field Equation ◽  
Experimental Work ◽  
Reynolds Equation ◽  
Pressure Field ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Theoretical Treatment ◽  
Hydrodynamic Journal Bearing

The application of a perturbation in terms of simple correlations for friction in turbulent Couette and ‘screw’ flows, together with a further empirical assumption consonant with the experimental work of Smith and Fuller (1), leads to a pressure field equation identical in form with the Reynolds equation. The load capacity of journal bearings throughout most of the superlaminar range may be represented by a single curve, and existing laminar solutions may be applied with the parameters modified by Reynolds number. The theory is compared with published experimental results, and with the most successful theoretical treatment (4). The correlations obtained confirm the adequacy of the theory to predict performance in the superlaminar régime.

Predictions of ultimate load capacity for pre-stressed concrete containment vessel model with BARC finite element code ULCA

2003 ◽  
Vol 30 (4) ◽  
pp. 437-471 ◽  
Author(s):  
S.M. Basha ◽  
R.K. Singh ◽  
R. Patnaik ◽  
S. Ramanujam ◽  
H.S. Kushwaha ◽  
...  
Keyword(s):  
Finite Element ◽  
Ultimate Load ◽  
Load Capacity ◽  
Finite Element Code ◽  
Ultimate Load Capacity ◽  
Containment Vessel

A Contribution to the Analysis of the Thermo-Hydrodynamic Lubrication of Porous Self-Lubricating Journal Bearings

2010 ◽  
Vol 297-301 ◽  
pp. 618-623 ◽  
Author(s):  
S. Boubendir ◽  
Salah Larbi ◽  
Rachid Bennacer
Keyword(s):  
Thermal Effects ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Porous Matrix ◽  
Journal Bearings ◽  
Governing Equations ◽  
Hydrodynamic Analysis ◽  
Result Show

In this work the influence of thermal effects on the performance of a finite porous journal bearing has been investigated using a thermo-hydrodynamic analysis. The Reynolds equation of thin viscous films is modified taking into account the oil leakage into the porous matrix, by applying Darcy’s law to determine the fluid flow in the porous media. The governing equations were solved numerically using the finite difference approach. Obtained result show a reduction in the performance of journal bearings when the thermal effects are accounted for and, this reduction is greater when the load capacity is significant.

scholarly journals A Comparative Elastohydrostatic Analysis of CFV- and Capillary-Compensated Multirecess Hydrostatic/Hybrid Journal Bearing Operating with Micropolar Lubricant

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Suresh Verma ◽  
Vijay Kumar ◽  
K. D. Gupta
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Study ◽  
Elastic Deformation ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Performance Characteristics ◽  
Constant Flow ◽  
Bearing System ◽  
Flow Valve

A comparative study on the performance characteristics of the flexible multirecess hydrostatic journal bearing system with constant flow valve and capillary restrictors has been presented considering the effect of micropolar parameters. The modified Reynolds equation for the flow of micropolar lubricant through the bearing has been solved using finite element method, and the resulting elastic deformation in the bearing shell has been determined iteratively. The results indicate that the micropolar parameters of the lubricant affect the performance of the flexible multirecess hydrostatic journal bearing system quite significantly.

scholarly journals Steady-state heat transfer analysis in a spherical domain revisited

2021 ◽  
Vol 347 ◽  
pp. 00006
Author(s):  
Jat du Toit ◽  
Christiaan Pretorius
Keyword(s):  
Differential Equation ◽  
Finite Element ◽  
Numerical Solution ◽  
Heat Transfer Analysis ◽  
Finite Element Code ◽  
Dimensionless Numbers ◽  
Galerkin Finite Element ◽  
Spherical Domain ◽  
Steady State Heat Transfer ◽  
The One

The paper discusses the numerical solution of the one-dimensional radially axi-symmetric non-linear second-order differential equation to model the conduction and radiation transfer through a spherical domain as a result of an exothermic heat source. The equation is transformed to a non-dimensional form. The dimensionless numbers emanating from the transformation represent the effect of the reaction rate, reaction type, activation energy, radiation and the convection on the temperature. The non-dimensional differential equation for the temperature distribution was previously solved using the Runge-Kutta-Fehlberg method coupled with a Shooting technique. In this paper the solution of the non-dimensional differential equation using an iterative Galerkin finite element method approach employing the Picard method is described. The commercial finite element code Comsol is also employed to solve the non-dimensional differential equation. The current study was motivated by inconsistencies that were observed in the previous results that were presented. Although the assumed underlying physics is used to evaluate the results, the study focuses purely on the numerical solution of the non-dimensional differential equation. The results obtained by the Galerkin finite element code and Comsol were found to be in exact agreement and also exhibit no inconsistencies.

Performance of textured foil journal bearing considering the influence of relative texture depth

2022 ◽  
pp. 135065012110729
Author(s):  
Guanghui Zhang ◽  
Kefan Xu ◽  
Jiazhen Han ◽  
Yanzhong Huang ◽  
Wenjie Gong ◽  
...  
Keyword(s):  
Iterative Method ◽  
Dynamic Characteristics ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Surface Texturing ◽  
Static And Dynamic Characteristics ◽  
Foil Bearing ◽  
Newton Raphson ◽  
Maximum Increment

Both foil structure and surface texturing have been widely used to improve bearing performance. However, there is little research on their combination, namely, textured gas foil bearing. This paper adopts the Reynolds equation as the pressure governing equation of bump-type foil journal bearing to study the influence of textures located on the top foil. The Newton-Raphson iterative method and the perturbation method are employed to obtain static and dynamic characteristics, respectively. Thereafter, based on three texture distribution types, further analysis about the effect of the relative texture depth and the textured portion is carried out. The results indicate that an appropriate arrangement of textures could improve the performance of gas foil bearing. For #1 texture distribution, the maximum increment of load capacity could exceed 10% when ω  =  1.4 × 105 r/min, ε  =  0.2.

Performance Analysis of Grooved Hydrodynamic Journal Bearing with Multi-Depth Textured Surface

2018 ◽  
Vol 10 (2) ◽  
Author(s):  
K.M Faez ◽  
S Hamdavi ◽  
T.V.V.L.N. Rao ◽  
H.H Ya ◽  
Norani M. Mohamed
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Textured Surface ◽  
Plain Bearing ◽  
Bearing Surface ◽  
Grooved Surface ◽  
Hydrodynamic Journal Bearing ◽  
Efficiency And Reliability ◽  
Capacity Performance

In recent research, theoretical studies and investigations for the textured surface of a hydrodynamic journal bearing has been widely used. This is due to the journal bearing’s performance in terms of load capacity which affects the system performance, efficiency and reliability. It has been proven that a textured surface and grooved surface have managed to improve the performance of journal bearings to some extent. In this work, the performance of a grooved hydrodynamic journal bearing has been analysed with a multi-depth textured surface. The study has been conducted using the modified Reynolds equation to numerically solve the load capacity and pressure distribution, respectively. From the results obtained, it was found that the surface complexity features on the journal bearing lowered the load capacity performance when compared to the plain bearing. The pressure, meanwhile, was distributed throughout the textured sections on the bearing surface, even though it was lower as compared to the plain bearing.

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