Pumping Action of Aligned Smooth Face Seals Due to Axial Vibrations—Theory

1984 ◽  
Vol 106 (3) ◽  
pp. 344-351
Author(s):  
M. Kaneta ◽  
Y. Jinnouchi ◽  
M. Fukahori
Keyword(s):  
Film Thickness ◽  
Flow Resistance ◽  
Analytical Study ◽  
Sinusoidal Oscillation ◽  
Periodic Fluctuation ◽  
Face Seals ◽  
Axial Vibrations

This is an analytical study of the mechanism of pumping action produced in two axially symmetrical disks. The disks have a continuous parallel film thickness between them, and one of them has a recess at the center and is subjected to a normal sinusoidal oscillation. It is found out that whether the pumping action is inward or outward depends upon a shift of phase between a variation of flow resistance due to a periodic fluctuation of the film thickness between seal faces and a variation of pressure in the recess.

Pumping Action of Aligned Smooth Face Seals Due to Axial Vibrations-Experiment

1986 ◽  
Vol 108 (1) ◽  
pp. 46-52
Author(s):  
M. Kaneta ◽  
M. Fukahori
Keyword(s):  
Film Thickness ◽  
Previous Investigation ◽  
Design Principles ◽  
Mechanical Seals ◽  
Face Seals ◽  
Axial Vibrations ◽  
Fundamental Design

The mechanism of pumping action caused by axially vibrating one of the seal faces with continuous parallel film thickness is clarified experimentally. The results obtained in the experiment confirm the theory developed in a previous investigation [11]. The fundamental design principles of mechanical seals are also described from the viewpoint of this pumping phenomenon.

Influence of Lubricant Inlet Film Thickness on Elastohydrodynamically Lubricated Contact Starvation

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
David Kostal ◽  
Petr Sperka ◽  
Petr Svoboda ◽  
Ivan Krupka ◽  
Martin Hartl
Keyword(s):  
Experimental Data ◽  
Film Thickness ◽  
Flow Resistance ◽  
Experimental Validation ◽  
Theoretical Models ◽  
Research Area ◽  
Theoretical Studies ◽  
Point Contacts ◽  
Lubricated Contact ◽  
Side Flow

The paper deals with an experimental study of an elastohydrodynamic contact under insufficient lubricant supply. Theoretical studies published in this research area focus mainly on the development of theoretical models, and there is a lack of experimental validation of the theoretical models. This paper presents original experimental results and aims to describe the starvation severity level as a function of the inlet film thickness and contact geometry. Experimental data are compared with an analytical model for point contacts published by Chevalier. The study was also extended to elliptical contacts to achieve a comparison with the different parameters of the side-flow resistance used by Damiens. Both models agree well with the experiments.

Effects of Two-Dimensional, Sinusoidal Roughness on the Load Support Characteristics of a Lubricant Film

1963 ◽  
Vol 85 (2) ◽  
pp. 258-262 ◽  
Author(s):  
R. A. Burton
Keyword(s):  
Shear Stress ◽  
Film Thickness ◽  
Analytical Study ◽  
Lubricant Film ◽  
Two Dimensional ◽  
Parallel Plates ◽  
First Order ◽  
Shear Elasticity ◽  
Net Load ◽  
Boundary Roughness

An analytical study is made of the effects of two-dimensional, sinusoidal roughness on pressure and shear stress in a lubricant film between two parallel plates engaged in steady, parallel, relative motion. The effects of pressure and heating upon viscosity, as well as shear elasticity are accounted for in the case where roughness height is small relative to film thickness. Second-order influences which contribute to net load support by the film are computed in terms of the first-order solution. The results give evidence as to when boundary roughness may be negligible in its influence on hydrodynamic film calculations. Most important, however, they give evidence of a type of instability which may contribute to film breakdown in some marginal lubrication situations.

Load Support and Leakage from Microasperity-Lubricated Face Seals

1969 ◽  
Vol 91 (4) ◽  
pp. 726-731 ◽  
Author(s):  
J. N. Anno ◽  
J. A. Walowit ◽  
C. M. Allen
Keyword(s):  
Pressure Drop ◽  
Film Thickness ◽  
Poiseuille Flow ◽  
Linear Velocity ◽  
Channel Height ◽  
Face Seal ◽  
Rotor Rotation ◽  
Lubricant Films ◽  
Face Seals ◽  
Lubricant Viscosity

Observations of load support from various shapes of microasperities placed on the surface of a rotary-shaft face seal indicate that all are comparable in this respect and generally follow the theory developed previously for cylindrical asperities. Both positive (protrusions) and negative (valleys) asperities produce similar load support, developing stable hydrodynamic lubricant films of the order of 10−5 in. for linear velocity of at least 50 in./sec, lubricant viscosity as low as 1 cp, and loads of the order of 100 pounds or higher. Variations in the film thickness with these parameters is predicted by the theory developed on the basis that an effective small tilt exists on the tops of the asperities. Leakage from microasperity-lubricated seals on the average follows the predictions of Poiseuille flow, with the exception that a significant effect of rotor rotation is observed. For a leakage channel height of 10−4 in., leakage was typically of the order of 0.2 in.3/hr for a pressure drop of 10 psi across the seal.

Laminar Flow Along a Vertical Wall

1968 ◽  
Vol 35 (4) ◽  
pp. 631-633 ◽  
Author(s):  
R. Haugen
Keyword(s):  
Thin Film ◽  
Boundary Layer ◽  
Laminar Flow ◽  
Film Thickness ◽  
Closed Form ◽  
Analytical Study ◽  
Vertical Wall ◽  
Mathematical Solution ◽  
Dimensionless Variables ◽  
Accelerating Flow

An analytical study is presented which describes the laminar accelerating flow of a thin film falling along a vertical wall. The approximate mathematical solution is given with emphasis on the growth and decrease of the boundary layer and film thickness, respectively. These resultant solutions are given in closed form and are found dependent upon two-dimensionless variables: φ2=3U0νgh02 and ζ2=1+2gh0x¯U02.

scholarly journals A New Approach for the Measurement of Film Thickness in Liquid Face Seals

2008 ◽  
Vol 51 (2) ◽  
pp. 140-149 ◽  
Author(s):  
T. Reddyhoff ◽  
R. S. Dwyer-Joyce ◽  
P. Harper
Keyword(s):  
Film Thickness ◽  
New Approach ◽  
Face Seals

Surface Films on Zircaloy-2 Samples Cracked in Neutral Aqueous NaCl by Stress Corrosion

1973 ◽  
Vol 31 ◽  
pp. 46-47
Author(s):  
R.A. Ploc
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Film Thickness ◽  
Stress Corrosion ◽  
Zirconium Dioxide ◽  
Surface Film ◽  
Surface Films ◽  
Continuous Layer ◽  
Transmission Electron ◽  
Product Film

Samples of low-nickel Zircaloy-2 (material MLI-788-see(1)), when anodically polarized in neutral 5 wt% NaCl solutions, were found to be susceptible to pitting and stress corrosion cracking. The SEM revealed that pitting of stressed samples was occurring below a 2000Å thick surface film which behaved differently from normal zirconium dioxide in that it did not display interference colours. Since the initial film thickness was approximately 65Å, attempts were made to examine the product film by transmission electron microscopy to deduce composition and how the corrosion environment could penetrate the continuous layer.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

The method of replication affects metal film granularity and resolution

1989 ◽  
Vol 47 ◽  
pp. 708-709
Author(s):  
George C. Ruben
Keyword(s):  
Electron Beam ◽  
High Resolution ◽  
Film Thickness ◽  
Single Molecule ◽  
Metal Film ◽  
Vertical Surface ◽  
High Resolution Imaging ◽  
Controllable Factors ◽  
Resolution Imaging

Single molecule resolution in electron beam sensitive, uncoated, noncrystalline materials has been impossible except in thin Pt-C replicas ≤ 150Å) which are resistant to the electron beam destruction. Previously the granularity of metal film replicas limited their resolution to ≥ 20Å. This paper demonstrates that Pt-C film granularity and resolution are a function of the method of replication and other controllable factors. Low angle 20° rotary , 45° unidirectional and vertical 9.7±1 Å Pt-C films deposited on mica under the same conditions were compared in Fig. 1. Vertical replication had a 5A granularity (Fig. 1c), the highest resolution (table), and coated the whole surface. 45° replication had a 9Å granulartiy (Fig. 1b), a slightly poorer resolution (table) and did not coat the whole surface. 20° rotary replication was unsuitable for high resolution imaging with 20-25Å granularity (Fig. 1a) and resolution 2-3 times poorer (table). Resolution is defined here as the greatest distance for which the metal coat on two opposing faces just grow together, that is, two times the apparent film thickness on a single vertical surface.

FILM THICKNESS DEPENDENCE OF HEAT TRANSMISSION INTO HELIUM

1981 ◽  
Vol 42 (C6) ◽  
pp. C6-825-C6-827
Author(s):  
P. Taborek ◽  
M. Sinvani ◽  
M. Weimer ◽  
D. Goodstein
Keyword(s):  
Film Thickness ◽  
Thickness Dependence ◽  
Heat Transmission
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