Magnetohydrodynamic lubrication flow between parallel plates

1966 ◽  
Vol 26 (3) ◽  
pp. 537-543 ◽  
Author(s):  
E. Roland Maki ◽  
Dennis C. Kuzma ◽  
Russell J. Donnelly
Keyword(s):  
Thrust Bearing ◽  
Lubrication Theory ◽  
Parallel Plates ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Theory And Experiment ◽  
Good Agreement

The magnetohydrodynamic lubrication flow in an externally pressurized thrust bearing is investigated both theoretically and experimentally. The ordinary magnetohydrodynamic lubrication theory for this bearing is extended to include fluid inertia effects. Very good agreement is obtained between theory and experiment.

Flow Characteristics of a Powder Lubricant in a Slider Bearing

2001 ◽  
Author(s):  
Manjunath Pappur ◽  
M. M. Khonsari
Keyword(s):  
Slip Velocity ◽  
Thrust Bearing ◽  
Volume Fraction ◽  
Flow Characteristics ◽  
Slider Bearing ◽  
Systematic Development ◽  
Powder Lubrication ◽  
Insight Into ◽  
Theory And Experiment ◽  
Good Agreement

Abstract This paper deals with a systematic development of theory of powder lubrication with the appropriate formalism based on the fundamentals of fluid mechanics. The theory is capable of predicting flow velocity, fluctuation (pseudo-temperature), powder volume fraction, and slip velocity at the boundaries. An extensive set of parametric simulations covering particle size, surface roughness, volumetric flow, load and speed are performed to gain insight into the performance of a powder lubricated thrust bearing. The results of simulations are compared to the published experimental results. Good agreement between the theory and experiment attests to the capability of the model and its potential for design of powder lubricated bearings.

Fluid Inertia Effects in Non-Newtonian Squeeze Films

1976 ◽  
Vol 98 (3) ◽  
pp. 409-411 ◽  
Author(s):  
A. F. Elkouh
Keyword(s):  
Load Capacity ◽  
Squeeze Film ◽  
Energy Integral ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
First Order ◽  
Integral Methods ◽  
Method Yield ◽  
Pseudoplastic Fluids ◽  
Good Agreement

The momentum and energy integral methods are used to study the effect of inertia on the behavior of a non-Newtonian (Power Law) squeeze film. It is shown that the inertia correction in the load capacity is more significant for pseudoplastic fluids, n < 1. For a Newtonian fluid, n = 1, the expressions obtained by using the energy integral method yield results identical to those obtained from a first-order iteration, and which are in good agreement with available experiments.

The tearing of an adhesive layer between flexible tapes pulled apart

1972 ◽  
Vol 52 (4) ◽  
pp. 639-656 ◽  
Author(s):  
A. S. Williamson
Keyword(s):  
Surface Tension ◽  
Adhesive Layer ◽  
Energy Dissipation Rate ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Pressure Sensitive ◽  
Polynomial Expression ◽  
Newtonian Viscous Fluid ◽  
Stable Flow ◽  
Good Agreement

The tearing of a pressure-sensitive (‘tacky’) adhesive is examined. Two flexible strips bonded by a layer of adhesive are passed between adjacent cylindrical guides and peeled apart, causing the adhesive layer to separate into two about a surface tension membrane. Treating the adhesive as a Newtonian viscous fluid, the slow-flow problem is solved by an iterative numerical scheme in which the surface tension membrane boundary in the vicinity of the region of separation is approximated by a shear-free boundary given by a sixth-degree polynomial expression. The energy dissipation rate, a measure of the ‘strength’ of the adhesive, is obtained from the flow.The solution method is also used to determine the similar flow induced by two counter-rotating rollers partially immersed in a large bath of fluid. The results are in fairly good agreement with available experimental data. The symmetrical eddies observed under the lowest point of the surface tension membrane in the stable flow between the rollers are reproduced in the solution, proving that fluid inertia effects are not essential for their existence.

Evaluation of Various Approximate Solutions for Fluid Inertia Effects on the Dynamic Performance of a Stepped Thrust Bearing

1985 ◽  
Vol 107 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Y. Haruyama ◽  
T. Kazamaki ◽  
A. Mori ◽  
H. Mori
Keyword(s):  
Film Thickness ◽  
Thrust Bearing ◽  
Stokes Equations ◽  
Dynamic Performance ◽  
Approximate Solutions ◽  
Time Dependent ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Dependent Term ◽  
Wide Range

Based on the Navier-Stokes equations in which the pressure is assumed to be constant across the film thickness, various approximate solutions and the exact one for the dynamic performance of an infinitely wide, stepped thrust bearing in a laminar flow regime are presented under the assumption of a small harmonic vibration. From comparison of the approximate solutions with the exact one, it is concluded that some kind of averaging approach in which the time dependent term is treated exactly while the convective inertia terms are averaged out across the film thickness gives close approximations in a wide range of designing conditions, and that the other kind of averaging approach in which all the inertia terms including the time dependent term are averaged out across the film thickness gives fairly good approximations.

The magnetohydrodynamic squeeze film

1964 ◽  
Vol 19 (3) ◽  
pp. 395-400 ◽  
Author(s):  
Dennis C. Kuzma ◽  
E. Roland Maki ◽  
Russell J. Donnelly
Keyword(s):  
Excellent Agreement ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Theory And Experiment

Magnetohydrodynamic squeeze films are investigated theoretically and experimentally. The theory of magnetohydrodynamic lubrication as applied to squeeze films is extended to include fluid-inertia effects and buoyant forces. Excellent agreement is obtained between theory and experiment.

Squeeze Film Flow Between Arbitrary Two-Dimensional Surfaces Subject to Normal Oscillations

1978 ◽  
Vol 100 (3) ◽  
pp. 316-322 ◽  
Author(s):  
J. A. Tichy ◽  
M. F. Modest
Keyword(s):  
Thrust Bearing ◽  
Analytic Solution ◽  
Film Flow ◽  
Oscillation Amplitude ◽  
Reynolds Numbers ◽  
Lubrication Theory ◽  
Squeeze Film ◽  
Two Dimensional ◽  
Surface Geometry ◽  
Inertia Effects

An analytic solution is presented for squeeze film flow with smooth, arbitrary, two-dimensional surface geometry. One surface undergoes sinusoidal oscillation toward the other. The oscillation amplitude is much smaller than the film thickness, which is in turn much smaller than the bearing length. The solution improves on the lubrication theory due to the inclusion of inertia effects. The solution to an illustrative problem is presented—the thrust bearing. The velocity field, pressure distribution and load differ significantly from those predicted by lubrication theory. The results show the lubrication solution for load and pressure to be in error by over 100 percent for Reynolds numbers as low as 5.

Experimental Evaluation of Sector-Shaped Hydrodynamic Thrust Bearings Under Translation and Transverse Vibration

1994 ◽  
Vol 116 (3) ◽  
pp. 521-527 ◽  
Author(s):  
Y. K. Wang ◽  
C. D. Mote
Keyword(s):  
Reynolds Number ◽  
Transverse Vibration ◽  
Thrust Bearing ◽  
Lubrication Theory ◽  
Fluid Inertia ◽  
Thrust Bearings ◽  
Spring Force ◽  
Bearing Load ◽  
The Mean ◽  
Simultaneous Translation

The bearing load of a plane inclined sector-shaped hydrodynamic thrust bearing, under simultaneous translation and transverse vibration, is measured experimentally. The results are used to evaluate the lubrication theory solutions. Consequently, both the influences of the unsteady film inertia, measured by the squeeze Reynolds number Res, and the convective film inertia, measured by the modified Reynolds number Re*, on load amplitude and phase are investigated. It is found that the inertia-neglected lubrication solutions underestimate: (1) the oscillatory component of the bearing load by 6.5 percent at Res = 1.0 and by 1.4 percent at Re* = 1.0, and (2) the mean component of the bearing load by 0.7 percent at Res = 1.0 and by 2.0 percent at Re* = 1.0 Moreover, the fluid inertia induces an equivalent negative spring force component which shifts the phase of the bearing load by 9.5 deg at Res =1.0 and by 4 deg at Re* = 1.0 as compared to the lubrication theory predictions. Hence it can be an important consideration when designing bearings for vibration control purposes.

scholarly journals Out-of-Plane Vibration of Curved Uniform and Tapered Beams with Additional Mass

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Hamdi Alper Özyiğit ◽  
Mehmet Yetmez ◽  
Utku Uzun
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Boundary Conditions ◽  
Natural Frequencies ◽  
Variable Cross ◽  
Additional Mass ◽  
Inertia Effects ◽  
Tapered Beam ◽  
Out Of Plane ◽  
Good Agreement

As there is a gap in literature about out-of-plane vibrations of curved and variable cross-sectioned beams, the aim of this study is to analyze the free out-of-plane vibrations of curved beams which are symmetrically and nonsymmetrically tapered. Out-of-plane free vibration of curved uniform and tapered beams with additional mass is also investigated. Finite element method is used for all analyses. Curvature type is assumed to be circular. For the different boundary conditions, natural frequencies of both symmetrical and unsymmetrical tapered beams are given together with that of uniform tapered beam. Bending, torsional, and rotary inertia effects are considered with respect to no-shear effect. Variations of natural frequencies with additional mass and the mass location are examined. Results are given in tabular form. It is concluded that (i) for the uniform tapered beam there is a good agreement between the results of this study and that of literature and (ii) for the symmetrical curved tapered beam there is also a good agreement between the results of this study and that of a finite element model by using MSC.Marc. Results of out-of-plane free vibration of symmetrically tapered beams for specified boundary conditions are addressed.

Morphology of Voltage-Triggered Ordered Wrinkles of a Dielectric Elastomer Sheet

2017 ◽  
Vol 84 (11) ◽  
Author(s):  
Guoyong Mao ◽  
Lei Wu ◽  
Xueya Liang ◽  
Shaoxing Qu
Keyword(s):  
High Voltage ◽  
Optical Sensor ◽  
Material Science ◽  
Dielectric Elastomer ◽  
Theoretical Studies ◽  
Science And Engineering ◽  
Future Design ◽  
Experimental And Theoretical Studies ◽  
Theory And Experiment ◽  
Good Agreement

Wrinkles widely existing in sheets and membranes have attracted a lot of attention in the fields of material science and engineering applications. In this paper, we present a new method to generate ordered (striplike) and steady wrinkles of a constrained dielectric elastomer (DE) sheet coated with soft electrodes on both sides subjected to high voltage. When the voltage reaches a certain value, wrinkles will nucleate and grow. We conduct both experimental and theoretical studies to investigate the wavelength and amplitude of the wrinkle. The results show a good agreement between theory and experiment. Moreover, the amplitude and wavelength of ordered wrinkles can be tuned by varying the prestretch and geometry of the DE sheet, as well as the applying voltage. This study can help future design of DE transducers such as diffraction grating and optical sensor.

Dynamic Characterization of an Integral Squeeze Film Bearing Support Damper for a Supercritical CO2 Expander

2017 ◽  
Author(s):  
Bugra Ertas ◽  
Adolfo Delgado ◽  
Jeffrey Moore
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Mechanical Impedance ◽  
Squeeze Film ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Damping Behavior ◽  
Impedance Testing ◽  
Stiffness And Damping ◽  
Onset Of Cavitation

The present work advances experimental results and analytical predictions on the dynamic performance of an integral squeeze film damper (ISFD) for application in a high-speed super-critical CO2 (sCO2) expander. The test campaign focused on conducting controlled orbital motion mechanical impedance testing aimed at extracting stiffness and damping coefficients for varying end seal clearances, excitation frequencies, and vibration amplitudes. In addition to the measurement of stiffness and damping; the testing revealed the onset of cavitation for the ISFD. Results show damping behavior that is constant with vibratory velocity for each end seal clearance case until the onset of cavitation/air ingestion, while the direct stiffness measurement was shown to be linear. Measurable added inertia coefficients were also identified. The predictive model uses an isothermal finite element method to solve for dynamic pressures for an incompressible fluid using a modified Reynolds equation accounting for fluid inertia effects. The predictions revealed good correlation for experimentally measured direct damping, but resulted in grossly overpredicted inertia coefficients when compared to experiments.

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