Influence of bearing surface irregularities on hybrid slot-entry journal bearing with electrically conducting lubricant

2019 ◽  
Vol 234 (8) ◽  
pp. 1185-1207
Author(s):  
Krishnkant Sahu ◽  
Satish C Sharma
Keyword(s):  
Journal Bearing ◽  
Equations Of Motion ◽  
Fluid Film ◽  
Navier Stokes ◽  
Bearing Surface ◽  
Navier Stokes Equation ◽  
Electrically Conducting ◽  
Surface Irregularities ◽  
Fluid Film Thickness ◽  
Effect Of Surface

This study concerns with the numerical simulation of a hybrid slot entry journal bearing lubricated with electrically conducting lubricant under the influence of magnetic field for both thermal and isothermal conditions. The Navier–Stokes equation has been used to formulate the flow of electrically conducting lubricant through slot restrictor and combining the Lorentz force in the equations of motion, together with the Ohm’s law and Maxwell equations. Further, the effect of surface irregularities on bearing surface is considered to analyse the performance of the slot-entry bearing. The surface irregularities asperity profile has been modelled in both axial as well as circumferential directions. Finite element method is used to solve the Modified MHD Reynolds equation. To compute the bearing performance characteristic parameters, a MATLAB source code based on Gauss–Seidel iteration method has been developed. A comparative numerical analysis has been carried out for an electrically conducting lubricant, Newtonian lubricant, bearing surface having irregularities and bearing with smooth surface. The numerically simulated results indicate that considering the bearing surface irregularities and MHD effects enhances the value of fluid film damping coefficients [Formula: see text] and the value of minimum fluid film thickness [Formula: see text].

A Study of Hole-Entry Grooved Surface Hybrid Spherical Journal Bearing Operating With Electrorheological Lubricant

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Adesh Kumar Tomar ◽  
Satish C. Sharma
Keyword(s):  
Journal Bearing ◽  
Fluid Film ◽  
Substantial Influence ◽  
The Finite Element Method ◽  
Bearing Surface ◽  
Stiffness Coefficients ◽  
Fluid Film Bearings ◽  
Grooved Surface ◽  
Fluid Film Thickness ◽  
Newtonian Behavior

Abstract The performances of the tribo-pairs are greatly influenced by introducing the grooved surfaces. Developments of the newer type of lubricants have made a great impact on the performance of fluid film bearings. This article investigates the non-Newtonian behavior of electrorheological lubricant on the performance of grooved hybrid spherical journal bearing. The effect of different arrangements of grooves, i.e., partially grooved or fully grooved on the bearing surface, has been studied. The finite element method is used to numerically simulate the results. Furthermore, a parametric study is performed for optimizing the groove attributes. The present work demonstrates that the different grooved arrangements have a substantial influence on the bearing performance. It is revealed that the provision of grooves on the bearing surface decreases frictional losses and enhances the stiffness coefficients of the bearing. Furthermore, numerically simulated results indicate that the electrorheological lubricant enhances the value of minimum fluid film thickness and the stiffness coefficients (S¯xxandS¯yy) of spherical hybrid journal bearing. Improved bearing performance can be achieved by using the optimized grooved attributes together with the electrorheological lubricant.

A study on performance of slot entry hybrid journal bearing considering effect of surface irregularities

2018 ◽  
Vol 70 (6) ◽  
pp. 1094-1109 ◽  
Author(s):  
Krishnkant Sahu ◽  
Satish C. Sharma
Keyword(s):  
Journal Bearing ◽  
Three Dimensional ◽  
Fluid Film ◽  
Element Formulation ◽  
Content Type ◽  
Lubricant Flow ◽  
Surface Irregularities ◽  
Order Of Magnitude ◽  
Fluid Film Thickness ◽  
Film Stiffness

PurposeThis study aims to deal with the performance of symmetric/asymmetric slot entry hybrid journal bearing system considering the effect of three dimensional irregularities in the analysis.Design/methodology/approachThe asperity profile of three-dimensional irregularities has been modeled in both circumferential and axial directions. To compute the bearing performance characteristics parameter, finite element formulation of governing Reynolds equation has been derived using Galerkin’s technique.FindingsBased on the numerically simulated results, it has been observed that the three-dimensional irregularities enhance the value of minimum fluid film thickness (h̄min), lubricant flow (Q̄) and fluid film damping coefficients (C̄11,C̄22) approximately by order of magnitude of 24-26, 43-51 and 18-66 per cent, respectively, for the case of asymmetric slot entry configuration. Whereas, the values of fluid film stiffness coefficients (S̄11,S̄22) and threshold speed (ω̄th) reduces approximately by order of 1-6 and 0-3 per cent, respectively, for the case of symmetric slot entry configuration.Originality/valueThe present paper describes that the influence of three-dimensional irregularities on bearing surface on the performance of slot entry hybrid journal bearing is original in literature gaps. The numerically simulated results presented in this study are expected to be quite useful to the bearing designers.

Performance Analysis of a Nonrecessed Hybrid Conical Journal Bearing Compensated With Capillary Restrictors

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Prashant G. Khakse ◽  
Vikas M. Phalle ◽  
S. S. Mantha
Keyword(s):  
Performance Analysis ◽  
Film Thickness ◽  
Journal Bearing ◽  
Fluid Film ◽  
Load Parameter ◽  
Radial Load ◽  
Wide Range ◽  
Bearing Stiffness ◽  
Fluid Film Thickness ◽  
Film Stiffness

The present paper deals with the performance analysis of a nonrecessed hole-entry hydrostatic/hybrid conical journal bearing with capillary restrictors. Finite element method has been used for solving the modified Reynolds equation governing the flow of lubricant in the clearance space of journal and bearing. The hole-entry hybrid conical journal bearing performance characteristics have been depicted for a wide range of radial load parameter (W¯r  = 0.25–1.5) with uniform distribution of holes at an angle of 30 deg in the circumferential direction. The numerically simulated results have been presented in terms of maximum fluid film pressure, minimum fluid film thickness, lubricant flow rate, direct fluid film stiffness coefficients, direct fluid film damping coefficients, and stability threshold speed. However, the proposed investigation of nonrecess hole-entry hybrid conical journal bearing shows important performance for bearing stiffness and minimum fluid film thickness at variable radial load and at given operating speed.

Learning the Dynamics of Objects by Optimal Functional Interpolation

2012 ◽  
Vol 24 (9) ◽  
pp. 2457-2472
Author(s):  
Jong-Hoon Ahn ◽  
In Young Kim
Keyword(s):  
Functional Data ◽  
Continuity Equation ◽  
Particle Concentration ◽  
Equations Of Motion ◽  
Navier Stokes ◽  
Conserved Quantities ◽  
Time Varying ◽  
Science And Engineering ◽  
Navier Stokes Equation ◽  
Over Time

Many areas of science and engineering rely on functional data and their numerical analysis. The need to analyze time-varying functional data raises the general problem of interpolation, that is, how to learn a smooth time evolution from a finite number of observations. Here, we introduce optimal functional interpolation (OFI), a numerical algorithm that interpolates functional data over time. Unlike the usual interpolation or learning algorithms, the OFI algorithm obeys the continuity equation, which describes the transport of some types of conserved quantities, and its implementation shows smooth, continuous flows of quantities. Without the need to take into account equations of motion such as the Navier-Stokes equation or the diffusion equation, OFI is capable of learning the dynamics of objects such as those represented by mass, image intensity, particle concentration, heat, spectral density, and probability density.

Axial Leakage Flow-Induced Vibration of Thin Cylindrical Shell With Respect to Circumferential Vibration

2002 ◽  
Author(s):  
Katsuhisa Fujita ◽  
Atsuhiko Shintani ◽  
Masakazu Ono
Keyword(s):  
Cylindrical Shell ◽  
Equations Of Motion ◽  
Fluid Pressure ◽  
Navier Stokes ◽  
Leakage Flow ◽  
Thin Cylindrical Shell ◽  
Flow Induced Vibration ◽  
Navier Stokes Equation ◽  
Coupled Equations ◽  
Unstable Vibration

In this paper, the dynamic stability of a thin cylindrical shell subjected to axial leakage flow is discussed. In this paper, the third part of a study of the axial leakage flow-induced vibration of a thin cylindrical shell, we focus on circumferential vibration, that is, the ovaling vibration of a shell. The coupled equations of motion between shell and liquid are obtained by using Donnell’s shell theory and the Navier-Stokes equation. The added mass, added damping and added stiffness in the coupled equations of motion are described by utilizing the unsteady fluid pressure acting on the shell. The relations between axial velocity and the unstable vibration phenomena are clarified concerning the circumferential vibration of a shell. Numerical parametric studies are done for various dimensions of a shell and an axial leakage flow.

scholarly journals Thermo-Elastohydrodynamic Study on Textured Journal Bearing with High-Speed and High-Specific-Pressure

2019 ◽  
Vol 37 (4) ◽  
pp. 751-756 ◽  
Author(s):  
Lin Wang ◽  
Yu Zhang ◽  
Guoding Chen
Keyword(s):  
Elastic Deformation ◽  
High Speed ◽  
Journal Bearing ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Specific Pressure ◽  
Analysis Model ◽  
Navier Stokes Equation ◽  
Gear Transmission System ◽  
Load Carrying

The performance of supporting journal bearing of the star gear transmission system in the geared turbo fan engine (GTF) is analyzed. A thermal-elastohydrodynamic analysis model was developed for textured journal bearing used in high-speed and high-specific-pressure conditions. The Navier-Stokes equation, energy equation, and viscosity-temperature equation were calculated by the computational fluid dynamics method. The influence of elastic deformation on bearing thermal hydrodynamic performance was studied in detail. The results indicate that the elastic deformation has an influence on the distribution of oil temperature and oil pressure. Besides, a comparative thermo-elastohydrodynamic analysis was conducted between the textured bearing and the un-textured bearing, and the discrepancies of maximum oil pressure, load carrying capacity and the maximum oil temperature are few. However, the textured bearing has a lower elastic deformation than the un-textured bearing.

PARTICLE DYNAMICS SIMULATIONS OF THE NAVIER–STOKES FLOW WITH HARD DISKS

2004 ◽  
Vol 15 (10) ◽  
pp. 1413-1424 ◽  
Author(s):  
TATSUYA ISHIWATA ◽  
TERUYOSHI MURAKAMI ◽  
SATOSHI YUKAWA ◽  
NOBUYASU ITO
Keyword(s):  
Equations Of Motion ◽  
Local Equilibrium ◽  
Flow Simulation ◽  
Quantitative Agreement ◽  
Particle Dynamics ◽  
Navier Stokes ◽  
Hard Disks ◽  
Navier Stokes Equation ◽  
Dynamics Simulations ◽  
Energy And Momentum

Flow simulation with a particle dynamics method is studied. The fluid is made of hard particles which obey the Newtonian equations of motion and the collisions between particles are elastic, that is, energy and momentum are conserved. The viscosity appears autonomously together with the local equilibrium state. When a particle collides with a nonslip boundary, a new velocity is given randomly from the thermal distribution if the wall is isothermal, or a random reflection angle is selected if the wall is adiabatic. Shear viscosity is estimated from simulations of plane Poiseuille flow together with the confirmation that the system obeys the Navier–Stokes equation. Flows past a cylinder are also simulated. Depending on the Reynolds number up to 106, flow patterns are properly reproduced, and Kármán vortex shedding is observed. The estimated values of drag coefficient show quantitative agreement with experiments.

Effect of partial grooving on the performance of hydrodynamic journal bearing

2017 ◽  
Vol 69 (4) ◽  
pp. 574-584 ◽  
Author(s):  
Anil B. Shinde ◽  
Prashant M. Pawar
Keyword(s):  
Carrying Capacity ◽  
Power Loss ◽  
Journal Bearing ◽  
Fluid Film ◽  
Frictional Torque ◽  
Load Carrying Capacity ◽  
Bearing Surface ◽  
Film Pressure ◽  
Content Type ◽  
Load Carrying

Purpose This study aims to improve the performance of hydrodynamic journal bearings through partial grooving on the bearing surface. Design/methodology/approach Bearing performance analysis is numerically carried out using the thin film flow physics of COMSOL Multiphysics 5.0 software. Initially, the static performance analysis is carried out for hydrodynamic journal bearing system with smooth surface, and the results of the same are validated with results from the literature. In the later part of the paper, the partial rectangular shape micro-textures are modeled on bearing surface. The effects of partial groove pattern on the bearing performance parameters, namely, fluid film pressure, load carrying capacity, frictional power loss and frictional torque, are studied in detail. Findings The numerical results show that the values of maximum fluid film pressure, load carrying capacity, frictional power loss and frictional torque are considerably improved due to deterministic micro-textures. Bearing surface with partial groove along 90°-180° region results in 81.9 per cent improvement in maximum fluid film pressure and 75.9 per cent improvement in load carrying capacity as compared with smooth surface of journal bearing, with no increase in frictional power loss and frictional torque. Maximum decrease in frictional power loss and frictional torque is observed for partially grooving along 90°-360° region. The simulations are supported by proof-of-concept experimentation. Originality/value This study is useful in the appropriate selection of groove parameters on bearing surface to the bearing performance characteristics.

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