Thermal Effects in Externally Pressurized Conical Bearings With Variable Viscosity

1988 ◽  
Vol 110 (2) ◽  
pp. 201-211 ◽  
Author(s):  
J. S. Kennedy ◽  
Prawal Sinha ◽  
Cz. M. Rodkiewicz
Keyword(s):  
Angular Velocity ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Film Thickness ◽  
Thermal Effects ◽  
Variable Viscosity ◽  
Load Capacity ◽  
Coupled Partial Differential Equations ◽  
Governing System ◽  
Conical Bearing

The influence of varying slider temperature on the characteristics of a conical bearing with constant film thickness rotating with a uniform angular velocity is examined. The fluid is considered to be incompressible and the viscosity is assumed to vary exponentially with temperature. The governing system of coupled partial differential equations in conical coordinates is solved numerically using finite difference method to yield the various bearing characteristics. The results show that maintaining the slider at temperature lower than that of the pad causes an increase in the load capacity of the bearing.

Convection and Dissipation Effects in Oil Lubricated Conical Bearings With Variable Viscosity

1991 ◽  
Vol 113 (2) ◽  
pp. 339-342 ◽  
Author(s):  
Prawal Sinha ◽  
C. M. Rodkiewicz
Keyword(s):  
Angular Velocity ◽  
Arbitrary Constant ◽  
Energy Equation ◽  
Variable Viscosity ◽  
Load Capacity ◽  
Dissipation Function ◽  
Governing System ◽  
Conical Bearing ◽  
The Finite Difference Method ◽  
Energy Equations

The influence of the inclusion of convection and dissipation terms in the energy equation, on the characteristics of a conical bearing with constant film thickness, rotating with a uniform angular velocity is examined. The slider temperature is taken to be an arbitrary constant, greater, equal or smaller, than the assumed constant temperature of the pad. The fluid is considered to be incompressible and the viscosity is assumed to vary exponentially with temperature. The governing system of coupled momentum and energy equations, in conical coordinates, is solved numerically using the finite difference method to yield the various bearing characteristics. The results show that the inclusion of dissipation function alone leads to an underestimation of load capacity and torque, whereas the inclusion of convection terms alone leads to an overestimation of the same.

Theoretical Research on Aerostatic Rectangular Guideways with Finite Difference Method

2007 ◽  
Vol 339 ◽  
pp. 371-376 ◽  
Author(s):  
Xiao Feng Zhang ◽  
Bin Lin
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Film Thickness ◽  
Pressure Distribution ◽  
Difference Method ◽  
Load Capacity ◽  
Theoretical Research ◽  
Orifice Diameter ◽  
Supply Pressure ◽  
Design And Manufacture

The load capacity and stiffness of the aerostatic rectangular guideways, which apply annular orifice restrictor and porous restrictor respectively, were analyzed with finite difference method in this paper. A program for solving the pressure distribution, load capacity and stiffness is programmed with VB. The calculated results show that the rise of supply pressure is good for improving the load capacity and stiffness of guideways. The decrease of the orifice diameter in annular orifice restriction and the permeability in porous restriction is advantageous to improve the stiffness of guideways, but both the corresponding bearing clearance and load capacity decrease. In both the annular restriction and porous restriction, the best film thickness which make the stiffness maximum exists under the definite supply pressure and parameter of the restrictor. Under the same supply pressure, the load capacity and stiffness of porous restriction is higher than the orifice restriction. Meanwhile, the design and manufacture of porous restrictor is simple. The porous restrictor is the perfect restrictor of aerostatic guideways.

Combined Influence of Misalignment and Orifice Diameter on the Static Performances of Hydrostatic, Water-Lubricated Journal Bearings

2014 ◽  
Vol 607 ◽  
pp. 608-611
Author(s):  
Hui Hui Feng ◽  
Chun Dong Xu ◽  
Feng Feng Wang
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Film Thickness ◽  
Power Loss ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Orifice Diameter ◽  
Rigid Rotor ◽  
Static Performance

The water-lubricated bearings have gained an increasing focus to overcome the disadvantages of the oil film bearings and gas bearings. In this paper, the influences of orifice diameter in aligned and misaligned conditions on the static performance of two hydrostatic, four-recess, water-lubricated journal bearings used to support a rigid rotor, are investigated. The steady Reynolds equation for the journal bearing for the turbulent bulk flow and the film thickness expression considering tilting angles are used and numerically solved by finite difference method. Results demonstrate that the static performances, such as the quality, power loss and temperature rise are affected by the tilting angles, orifice diameter to some degree.

Numerical Analysis of the Lubrication Performances for Ultra-Thin Gas Film Lubrication of Magnetic Head/Disk With a New Finite Difference Method

Tribology ◽  
2005 ◽  
Author(s):  
Ping Huang ◽  
Hongzhi Wang ◽  
Langui Xu ◽  
Yonggang Meng ◽  
Shizhu Wen
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Film Thickness ◽  
Difference Method ◽  
Magnetic Head ◽  
Balance Position ◽  
Pressure Distributions ◽  
Load Carrying ◽  
Squeeze Effect ◽  
Film Lubrication

In the present paper, a new iterative algorithm of finite difference method to numerically solve the lubrication problems of magnetic head/disks under ultra thin gas film thickness is introduced. Pressure distributions are calculated when a slider deviates slowly or abruptly from the balance position due to perturbations. The results show that when the slider moves in the film thickness direction, the pressure always tends to force the slider back to the balance position. Steady flying simulations show that the pitch angle is the sensitive parameter to the load carrying capacity of the slider, which should be carefully controlled in design. Squeeze effect is apparent when abrupt movements or rotations happen, which can avoid, to some extent, fatal damages due to vibration or uncertain interferences.

Analysis of Hybrid (Hydrodynamic/Hydrostatic) Journal Bearing

2013 ◽  
Vol 650 ◽  
pp. 385-390 ◽  
Author(s):  
Vijay Kumar Dwivedi ◽  
Satish Chand ◽  
K.N. Pandey
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Gas Turbines ◽  
High Speed ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Load Capacity ◽  
Natural Boundary Condition ◽  
Dimensional Solution

The Hybrid (hydrodynamic/ hydrostatic) journal bearing system has found wide spread application in high speed rotating machines such as compressors, gas turbines, steam turbines, etc. The present studies include solution of Reynolds equation for hydrodynamic journal bearing with infinitely long approximation (ILA), infinitely short bearing approximation (ISA) and finite journal bearing approximation. Further Finite Journal bearing approximation considers two dimensional solution of Reynolds equation with natural boundary condition, which cannot be solved by analytical method. So, here the solutions for finite journal bearing have been done with finite difference method (a MATLAB® code is prepared for finite difference method) to get bearing performance parameters such as load capacity, Sommerfeld no., etc.

Analysis of a non-constant gap externally pressurized conical bearing with temperature and pressure dependent viscosity

2000 ◽  
Vol 214 (5) ◽  
pp. 699-710 ◽  
Author(s):  
P Sinha ◽  
P Chandra ◽  
S Bhartiya
Keyword(s):  
Load Capacity ◽  
Rotational Inertia ◽  
Governing System ◽  
Lubricant Flow ◽  
Pressure Dependent Viscosity ◽  
Significant Difference ◽  
Conical Bearing ◽  
Significant Change ◽  
Dependent Viscosity ◽  
Energy Equations

The present paper analyses an externally pressurized non-constant gap conical bearing rotating with a uniform angular velocity. The lubricant is assumed to be incompressible and its viscosity varies with both pressure and temperature. Although the inertia effect due to lubricant flow has been neglected, rotational inertia is taken into account. The governing system of coupled momentum and energy equations, in conical coordinates, is solved numerically using the finite difference method, to determine various bearing characteristics. The effect of the viscosity-pressure exponent, , on various characteristics of the bearing has been studied. It is seen that variation of does not produce any significant change in the load capacity for convergent and constant gap conical bearings. For the divergent gap also, no significant difference is seen when the gap is slightly divergent. However, for highly divergent gaps, the load capacity increases with an increase in . It is also seen that variation in does not produce any significant change in torque of the bearing.

Effect of Turbulence and Offset Loading on the Performance of a Single Pad Externally Adjustable Fluid Film Bearing

2012 ◽  
Author(s):  
B. Satish Shenoy ◽  
Rammohan S. Pai B. ◽  
Raghuvir Pai B. ◽  
Shrikanth Rao D.
Keyword(s):  
Steady State ◽  
Finite Difference ◽  
Aspect Ratio ◽  
Finite Difference Method ◽  
Difference Method ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Fluid Film ◽  
Wide Range ◽  
Steady State Performance

Paper deals with the effect of turbulence on steady state performance characteristics of an eccentrically loaded 120° single pad externally adjustable fluid film bearing. The bearing has an aspect ratio of one and operates over a wide range of eccentricity ratios and adjustments. Two load-offset positions (β/χ) of 0.45 and 0.55 are considered in the present analysis. Reynolds equation incorporated with the Linearized turbulence model of Ng and Pan is solved numerically using finite difference method. A comparative study predicts that, load capacity of a bearing operating with β/χ = 0.55 and Re = 16000 is superior for negative radial and tilt adjustment configuration of the pad.

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