Showing papers in "Tribology Transactions in 1984"
TL;DR: In this paper, an optical profilometer has been developed which provides a noncontact method of obtaining surface characteristics from a magnetic medium, which is useful to predict tribological and magnetic performances of the head-media interface.
Abstract: Conventional surface-characterization techniques either are not sophisticated enough to provide complete surface-topographical data or cannot be employed because of the relatively low hardness of magnetic media. An optical profilometer has been developed which provides a noncontact method of obtaining surface characteristics from a magnetic medium. The system consists of a standard Leitz reflection microscope, a Mirau interferometer controlled by a piezoelectric transducer, a linear array of photodiode detectors, and a microcomputer. The combination yields a system that measures the optical-height variations of surfaces to a high degree of precision. This height variation is processed by a computer to provide surface-topographical statistical parameters, which are useful to predict tribological and magnetic performances of the head-media interface. Sample data of magnetic media (tape, floppy disk, and rigid disk) are presented. Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983
172 citations
TL;DR: In this paper, surface chemical and electron microscopic analyses show that the degraded rf sputtered MoS2 lubricant films are severely degraded by exposure to high humidity environments prior to wear testing.
Abstract: The endurance lives of rf sputtered MoS2 lubricant films are severely degraded by exposure to high humidity environments prior to wear testing. Surface chemical and electron microscopic analyses show that the degraded films are oxidized to form MoO3 and that the oxidation rate is a function of the orientation of the crystallites composing the films before any run-in or burnishing activity. If the crystallites are arranged with their basal planes parallel to the substrate surface, the films have lower reactivity (good stability) and longer endurance lives than film with randomly oriented crystallites. The results of surface analyses and wear tests are presented to support these observations. Auger electron spectroscopy results indicate that oxidation of the randomly oriented films (designated Type I films) occurs to a depth of at least 10 nm into the bulk of the films when they are exposed to adverse environments. Oxidation of films with coplanar orientations (Type II films), however, occurs only within 1 ...
137 citations
TL;DR: In this article, the experimental pressure and temperature results obtained when rotating a shaft in an eccentric lucite casing at velocities raging from 209 to 628 rad/s (2000 to 6000 rpm) were presented in terms of three-dimensional plots and contour maps.
Abstract: This paper describes the experimental pressure and temperature results obtained when rotating a shaft in an eccentric lucite casing at velocities raging from 209 to 628 rad/s (2000 to 6000 rpm). The results are presented in terms of three-dimensional plots and contour maps. Photographic evidence is presented to illustrate how the downstream and upstream regions of the cavity develop and evolve into the well-known finger patterns. A comparison between pressure and temperature profiles in air-saturated oil and carbon dioxide-saturated oil is presented; the origin and nature of the gases contained in the cavity are discussed. Three analytical models (Swift-Stieber, separation, Floberg) predicting the formation of the cavitation zone are presented and evaluated in light of the experimental results. A motion-picture supplement depicting these results is available upon request. Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference in Washington, D.C., October 5–...
76 citations
TL;DR: In this paper, an isothermal elastohydrodynamically-lubricated rectangular contact was evaluated numerically, where the elasticity and Reynolds equations were simultaneously solved by solving the simultaneous solution of elasticity, load, and material parameters.
Abstract: An isothermal elastohydrodynamically lubricated rectangular contact was evaluated numerically. This required the simultaneous solution of the elasticity and Reynolds equations. In the elasticity analysis the contact zone was divided into equal rectangular areas, and it was assumed that a uniform pressure was applied over each area. The elastohydrodynamic lubrication theory thus developed was used to investigate the influence of the dimensionless speed, load, and materials parameters on minimum film thickness. Ten cases were used in obtaining the minimum film thickness formula. Plots are shown that indicate the details of the pressure distribution, film shape, and flow. The characteristic pressure spike is clearly in evidence as is the parallel film shape through the central portion of the contact, with a minimum film thickness occurring near the outlet of the contact.
65 citations
TL;DR: In this paper, rates of adsorption and desorption, of di-isopropyldithiophosphoric acid and tetraisopropylthioperoxydiphosphate from hexade-cane on to steel, have been measured with 14C radiolabelled compounds.
Abstract: Rates of adsorption and desorption, of di-isopropyldithiophosphoric acid and tetraisopropylthioperoxydiphosphate from hexade-cane on to steel, have been measured wing 14C radiolabelled compounds. Concentration, temperature, and stirring dependence have been examined. The adsorption is surface controlled and the kinetics can be represented by a Langmuir model. Correlation of rate data with antiwear properties is examined. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983
52 citations
TL;DR: In this paper, the effects of various bearing parameters on ring speed were investigated and it was shown that none of the 16 bearing parameters investigated increased the bearing ring speeds to those values predicted by the isothermal bearing analysis.
Abstract: Testing of small high-speed floating-ring bearings, typical of those used in automotive turbochargers, revealed a discrepancy between ring speed measurements and ring speed prediction using isothermal bearing analysis. As bearing stability, energy loss, and load capacity are dependent on ring speed, an experimental program was undertaken to determine the effects of various bearing parameters on ring speed. The program results show that none of the 16 bearing parameters investigated increased the bearing ring speeds to those values predicted by the isothermal bearing analysis. In parallel with the experimental program, a thermal analysis was developed in which the effects of lubricant and bearing temperature on the ring speed of a floating-ring bearing way investigated. The ring speed predictions from this thermal floating-ring bearing model agree with the measured values except at the lowest and highest speeds tested. Therefore, for the type of floating-ring bearing design described in this paper, it is c...
43 citations
IBM1
TL;DR: In this paper, it is shown that the friction behavior shows little dependence on the chemistry of the binder and primarily on the thermomechanical response of the magnetic coating, and that in most commercial tapes, the friction is high when measured at high humidities (above 60).
Abstract: Whenever there are changes in surface chemistry of the magnetic tape caused by various tribological or environmental parameters, such as humidity and temperature, they may significanty increase the adhesive interaction between the magnetic tape and the drive components. Exposure to high humidity at elevated temperatures for extended periods can result in the hydrolytic degradation of the tape-binder system. The products of hydrolytic degradation have lower molecular weight and may be tacky in nature. Changes in the binder can be monitored by measuring molecular weight, extractable binder-to-lubricant ratio, and modulus of elasticity. A chemically stable binder system minimizes the risk of high friction. In the case of tapes tested at low humidity, the frictional behavior shows little dependence on the chemistry of the binder and primarily on the thermomechanical response of the magnetic coating. It is also noted that in most commercial tapes, the friction is high when measured at high humidities (above 60...
34 citations
TL;DR: In this paper, matched solutions for pressure distribution and bearing displacement field, taking into account the combined effects of bearing liner deformation as well as change in viscosity of the lubricant, are obtained by solving the respective governing equations using a suitable iteration scheme for eccentricity ratios up to unity.
Abstract: The deformation of a bearing, which can be of the order of the fluid film thickness when the bearing operates at large eccentricities, may affect the performance appreciably, and all the more so if the viscosity of the lubricant changes with pressure. In this paper, matched solutions for pressure distribution and the bearing displacement field, taking into account the combined effects of bearing liner deformation as well as change in viscosity of the lubricant, are obtained by solving the respective governing equations using a suitable iteration scheme for eccentricity ratios up to unity. The performance characteristics of the journal bearing and their variations with bearing flexibility, are studied with reference to eccentricity ratio and a deformation coefficient which is a measure of the flexibility of bearing shell.
34 citations
TL;DR: In this paper, it was shown that reaction of zinc di-n-octyldithiophosphate with peroxy radicals in laboratory experiments led to products which were ineffective as anti-wear agents.
Abstract: Previous work has shown that reaction of zinc di-n-octyldithiophosphate with peroxy radicals in laboratory experiments led to products which were ineffective as antiwear agents. These products have now been identified and a material balance obtained by the application of several analytical techniques. The principal reaction product was the disulfide species tetra-n-octylthioperoxydiphosphate. This compound was synthesized, tested, and found to be less effective than zinc di-n-octyldithiophosphate as an antiwear agent. Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983
29 citations
TL;DR: In this article, an experimental program was conducted to measure film temperature in all the pads of a 127mm (5-inch) diameter five-shoe tilting-pad journal bearing, load-between-pad configuration.
Abstract: An experimental program was conducted to measure film temperature in all the pads of a 127-mm (5-inch) diameter five-shoe tilting-pad journal bearing, load-between-pad configuration. Film temperature measurements were taken both in the circumferential and axial directions of the pads at different speeds, loads, and flows. The tests were conducted in speeds ranging from 3000 to 13 000 rpm, unit bearing load range of 34.5 × 104 to 172.4 × 104 N/m2 (50 to 250 psi) and at flows of 0.177, 0.252 and 0.379 L/s (2.8, 4.0, and 6.0 gpm). The actual power losses have also been compared to the theoretical power losses. Results of these tests are presented in this paper. Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983
26 citations
TL;DR: In this article, a sliding-friction experiment was conducted with ferrous-base metallic glasses (amorphous alloys) in contact with aluminum oxide at temperatures to 750°C in a vacuum.
Abstract: Sliding-friction experiments, X-ray photoelectron spectroscopy (XPS) analysis, and electron microscopy and diffraction studies were conducted with ferrous-base metallic glasses (amorphous alloys) in contact with aluminum oxide at temperatures to 750°C in a vacuum. Sliding-friction experiments were also conducted in argon and air atmosphere. The results of the investigation indicate that the coefficient of friction increases with increasing temperature to 350°C in vacuum. The increase in friction is due to an increase in adhesion resulting from surface segregation of boric oxide and/or silicon oxide to the surface of the foil. Above 500°C, the coefficient of friction decreased rapidly. The decrease correlates with the segregation of boron nitride to the surface. Contaminants can come from the bulk of the material to the surface upon heating and impart boric oxide and/or silicon oxide at 350°C and boron nitride above 500°C. The segregation of contaminants is responsible for the friction behavior. The amorph...
TL;DR: In this paper, a coned-face noncontacting seal is experimentally observed by means of three proximity probes monitoring the motion of the flexibly mounted stator, and various tilts of the stator are analyzed and the relative misalignment between stator and rotor is found.
Abstract: The dynamic behavior of a coned-face noncontacting seal is experimentally observed by means of three proximity probes monitoring the motion of the flexibly mounted stator. The various tilts of the stator are analyzed and the relative misalignment between stator and rotor is found. The effects of both the rotor runout and the flexible support on the relative misalignment are discussed. The tests demonstrate both stable and transition to unstable modes of seal operation. Reasons for failure and other phenomenon during stable seal operation are explained. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983
TL;DR: In this paper, an analysis for reciprocating sliding seals and pumping rings with an arbitrary clearance between the seal and rod and preload caused by axial tightening of the gland follower is presented.
Abstract: An analysis is presented for reciprocating sliding seals and pumping rings with an arbitrary clearance between the seal and rod and preload caused by axial tightening of the gland follower. The analysis is implemented by a fourth-order Runge-Kutta technique applied to the fluid equations in combination with a simple plane strain finite-element calculation for the seal. Results are presented for a variety of pressure differentials and preloads for both outstroke and instroke and both for soft elastomers and hard-filled PTFE material. Preload and initial clearance are shown to play an important role in seal and pumping-ring performance. Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983
TL;DR: A review of friction theories relevant to the interaction between magnetic-recording-device components (hard, inelastic materials) and viscoelastic polymeric materials used in the manufacture of flexible, magnetic tape is presented in this paper.
Abstract: A review of friction theories relevant to the interaction between magnetic-recording-device components (hard, inelastic materials) and viscoelastic, polymeric materials used in the manufacture of flexible, magnetic tape is presented. Tabor's classical theory of adhesion with appropriate deformation and shear-strain rates, as well as Hegmon's theory of hysteresis friction, adequately describes the frictional behavior. Other sources of adhesional friction are stiction, meniscus, and microcapillary evacuation. For magnetic-recording-tape applications, the adhesion component of friction is responsible for the major part of the observed friction, except near the softening temperature for the magnetic-coating layer, where the loss tangent becomes very high, or in the case of rough surfaces for which hysteresis friction is significant. From a magnetic-tape design standpoint, the real area of contact (which directly affects adhesional friction) can be minimized by increasing the complex modulus of elasticity of t...
TL;DR: In this paper, a 50mm diameter, spiral-groove face seal was used to seal liquid oxygen at 5.17 MPa pressure and operating at surface speeds of 183 m/s.
Abstract: Analyses and predicted performance of a 50-mm diameter, spiral-groove face seal to seal liquid oxygen at 5.17 MPa pressure, and operating at surface speeds of 183 m/s are described. The pressure-balanced spiral-groove concept is introduced that circulates spiral-groove flow independent of leakage flow. Independent flow paths preclude overheating from vaporization and consequent flow blockage. The analysis accounts for fluid turbulence and inertia, thermoelastic distortions, and dynamic response. An operating-range map was developed as a function of speed and pressure. The fluid-film analysis is summarized in the Appendix.
TL;DR: In this paper, an analytical approach was developed for the difficult problem of predicting the dynamic variation in fluid-film thickness of elastic-isoviscous line contacts under isothermal conditions, which was extended to the lubrication of compliant layered surfaces.
Abstract: An analytical approach was developed for the difficult problem of predicting the dynamic variation in fluid-film thickness of elastic-isoviscous line contacts under isothermal conditions. A numerical solution procedure was constructed and applied to the experiments of Hirano and Murakami who were investigating the lubrication of O-ring seals. Reasonable agreement was obtained. The present approach was extended to the lubrication of compliant layered surfaces as part of a study of human ankle joint lubrication. Although dependent on many assumptions, the present analysis provided a simple method for predicting the film thickness in both Hertzian and non-Hertzian contacts subject to cyclic time-varying loads and entrainment velocities. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 16–20, 1983
TL;DR: In this article, a comparison is made between film thicknesses determined by point and by line contact, and it is shown that the difference between the two was negligible. This is useful experimentally as point contact devices are much easier to build and use than line contact devices.
Abstract: This paper is in two parts. In the first, a comparison is made between film thicknesses determined by point and by line contact. The two are shown to give identical results. In the second part, fourteen test fluids were chosen to provide a variety of molecular structures. Eight polymers were studied at several concentration. A considerable amount of viscosity loss was observed at both point and line contacts. The difference between the two was negligible. This is important a it shows that the polymer molecules were moving straight through the contact and not going round the point contact. This is useful experimentally as point contact devices are much easier to build and use than line contact devices. The viscosity loss under EHL conditions was found to be 10 to 20 percent larger than that observed in a capillary high-shear viscometer. This is thought to be due to the completely different stress pattern in the two. The entry viscosity of the polymer-thickened oil differs hardly at all from the straight oi...
TL;DR: In this paper, the relationship between the theoretical tensile and the shear strengths and the friction properties of metals in contact with diamond, boron nitride, silicon carbide, manganese-zinc ferrite, and the metals themselves in vacuum was investigated.
Abstract: The relation between the theoretical tensile and the shear strengths and the friction properties of metals in contact with diamond, boron nitride, silicon carbide, manganese-zinc ferrite, and the metals themselves in vacuum was investigated. The relationship between the actual shear strength and the friction properties of the metal was also investigated. An estimate of the theoretical uniaxial tensile strength was obtained in terms of the equilibrium surface energy, interplanar spacing of the planes perpendicular to the tensile axis, and the Young's modulus of elasticity. An estimate of the theoretical shear strength for metals was obtained from the shear modulus, the repeat distance of atoms in the direction of shear of the metal, and the interplanar spacing of the shear planes. The coefficient of friction for metals was found to be related to the theoretical tensile, theoretical shear, and actual shear strengths of metals. The higher the strength, of the metal, the lower the coefficient of friction. Pre...
TL;DR: In this paper, aqueous polyglycol hydraulic fluids are found to give very low elastohydrodynamic film thicknesses and the pressure-viscosity coefficient appears to be inversely related to free volume.
Abstract: Commercial aqueous polyglycol hydraulic fluids are found to give very low elastohydrodynamic film thicknesses. By studying mixtures of polyglycol, monoglycol, and water, it is shown that this is became the pressure-viscosity coefficients of polyglycol and monoglycol fall very sharply when they are mixed together or when water is added. Over the polyglycol, monoglycol, water mixture range, pressure-viscosity coefficient appears to be inversely related to free volume. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983
TL;DR: In this article, the effect of extremely small slip amplitudes (0 to 5 μm) on transitions in the fretting process, such as initiation of surface damage, development of severe surface damage and microcrack initiation and the development of mild wear, was investigated.
Abstract: The effect of extremely small slip amplitudes (0 to 5 μm) on transitions in the fretting process, such as initiation of surface damage, development of severe surface damage, microcrack initiation and the development of mild wear, was investigated. For SAE 52100 against SAE 52100 steel, the minimum slip amplitude associated with the onset of mild oxidation or surface staining was approximately 0.06 μm. Studies at higher amplitudes of motion indicated a transition from minimal surface damage to severe or significant damage at 2.8 μm. A further slight increase in amplitude to approximately 3.0 μm resulted in a transition into a regime characterized by fatigue crack formation. These transformations were found to be influenced to some extent by material composition and hardness. The onset of severe surface damage occurred at 1.1 μm for SAE 52100 against SAE 1018 and at 0.5 μm for a nickel chrome Hastelloy B alloy against SAE 1018 steel. In general, the amplitude of microslip characterizing the transition from ...
TL;DR: In this paper, a theoretical analysis of the O-ring elastic and plastic extrusion process is developed and test results up to 350 MPa are shown to support the analysis, and the resulting extrusion fail-loads are examined as function of seal geometry, material properties, and load rates.
Abstract: It is generally recommended by most manufacturers to keep working pressures of O-ring seals below 10 MPa (20 MPa with backup rings) and clearances below 0.15 mm, or else they might fail by extrusion. For many applications, and especially for large one-shot impact devices, these limits are much too low, and more realistic limits may be set through better understanding of the failure modes. A theoretical analysis of the O-ring elastic and plastic extrusion process is developed and test results up to 350 MPa are shown to support the analysis. The resulting extrusion fail-loads are examined as function of seal geometry, material properties, and load rates. Some design recommendations and further research efforts are discussed. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 16–20, 1983
TL;DR: In this article, the analysis and design of a 50mm diameter floating-ring helium buffer seal are described. Butterworth et al. incorporated Rayleigh-step lift pads to provide hydrodynamic forces to separate the rings from the shaft.
Abstract: The analysis and design of a 50-mm diameter floating-ring helium buffer seal are described. The seal rings incorporated Rayleigh-step lift pads to provide hydrodynamic forces to separate the rings from the shaft. Maximum surface speed is 183 m/s (600 fps) and maximum buffer gas pressure is 1389 kPa (200 psia). An operating range map was computed as a function of speed and pressure. Contradictory problems arise due to excessive friction preventing ring tracking at low-speed, high-pressure conditions and insufficent friction to retard inertia driven motions at high-speed, low-pressure conditions. Steady-state and dynamic analyses and performance are described, as well as the results of thermal studies.
TL;DR: In this article, a study of fluorinated telomers, especially fatty acids and their amine salts, for boundary lubrication (antiwear conditions) is described, and the antiwear effectiveness of these fluorinated compounds is compared with a commercial additive, zinc di-n-butyl dithiophosphate (ZDTP).
Abstract: Many studies have been published on the use of solid fluorinated compounds as lubricants and lubricant additives, but much less has been done with oil-soluble fluorinated additives. This paper describes a study of fluorinated telomers, especially fatty acids and their amine salts, for boundary lubrication (antiwear conditions). The antiwear effectiveness of these fluorinated compounds is compared with a commercial additive, zinc di-n-butyl dithiophosphate (ZDTP). Modern analytical tools are used to study surface layers (XPS, automatic wetting balance), and wear particles (IR) to determine their antiwear mechanism. Special attention is given to fluorinated reaction film formation. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in Hartford, Connecticut, October 18–20, 1983
TL;DR: In this paper, light optical and scanning electron microscope studies were conducted to characterize the erosion resistance of polymethyl methacrylate (PMMA), polycarbonate (PC), polytetrafluoroethylene (PTFE), and ultra-high-molecular-weight polyethylene(UHMWPE).
Abstract: Light optical and scanning electron microscope studies were conducted to characterize the erosion resistance of polymethyl methacrylate (PMMA), polycarbonate (PC), polytetrafluoroethylene (PTFE) and ultra-high-molecular-weight-polyethylene (UHMWPE). Erosion was caused by a jet of spherical micro-glass beads at normal impact. During the initial stages of damage, the surfaces of these materials were studied using a profilometer. Material buildup above the original surface was observed on PC and PMMA. As erosion progressed, this buildup disappeared as the pit became deeper. Little or no buildup was observed on PTFE and on UHMWPE. UHMWPE and PTFE are the most resistant materials and PMMA the least. Favorable properties for high erosion resistance seem to be high values of ultimate elongation, and strain energy and a low value of the modulus of elasticity. Erosion-rate-versus-time curves of PC and PTFE exhibit incubation, acceleration and steady state periods. A continuously increasing erosion rate period was observed however for PMMA instead of a steady state period. At early stages of damage and at low impact pressure material removal mechanisms appear to be similar to those for metallic materials.
TL;DR: In this article, correlation equations are presented to predict m and micron for two modern traction fluids based on the regression analysis of 334 separate traction disk machine experiments, and the effects of contact pressure, temperature, surface velocity, ellipticity ratio are examined.
Abstract: In the analysis of rolling-sliding concentrated contacts, such as gears, bearings and traction drives, the traction characteristics of the lubricant are of prime importance. The elastic shear modulus and limiting shear stress properties of the lubricant dictate the traction/slip characteristics and power loss associated with an EHD contact undergoing slip and/or spin. These properties can be deducted directly from the initial slope m and maximum traction coefficient micron of an experimental traction curve. In this investigation, correlation equations are presented to predict m and micron for two modern traction fluids based on the regression analysis of 334 separate traction disk machine experiments. The effects of contact pressure, temperature, surface velocity, ellipticity ratio are examined. Problems in deducing lubricant shear moduli from disk machine tests are discussed. Previously announced in STAR as N83-20116
TL;DR: In this paper, the authors showed that aluminum alloy surfaces with a high percentage of MgO in the oxide layer were wetted by naphthenic oil and oleic acid.
Abstract: In oil/water/solid contact angle experiments, aluminum alloy surfaces with a high percentage of MgO in the oxide layer were wetted by naphthenic oil and naphthenic oil containing 1 percent oleic acid. The opposite behavior, poor wetting, was observed on alloy surfaces of almost pure aluminum oxide. On the latter surfaces, however, oil wetting was increased by decreasing the pH and by adding magnesium ions to the water being displaced. The same trends in wetting were observed in interactions between pure oxide powders and a commercial rolling emulsion containing naphthenic oil and oleic acid. The implications of this behavior to process lubrication and surface quality in aluminum rolling are discussed. Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983
TL;DR: In this paper, a finite-length plane journal bearing with a spatially tilted shaft is analyzed for the pressure, velocity, and temperature profiles of the case under study, where the effect of viscous dissipation is taken into account.
Abstract: The analysis presented herein deals with the evaluation of the pressure, velocity, and temperature profiles in a finite-length plane journal bearing. The geometry of the case under study consists of a spatially tilted shaft. The two-dimensional Reynolds equation accounts for the variation of the clearance gap h with x and z and is used to model the pressure field. The latter is solved for a variety of shaft tilt angles and then used to calculate the two-dimensional flow field. Finally, the flow field is used in the energy equation to solve for the film temperature profile, when the effect of viscous dissipation is taken into account.
TL;DR: In this article, the rates of mineral oil oxidation and organometallic compound formation at temperatures approaching those existing in concentrated contacts were analyzed and quantified using a thin-film microreactor.
Abstract: This study was conducted to determine the rates of mineral oil oxidation and organometallic compound formation at temperatures approaching those existing in concentrated contacts. The thin-film microreactor was used so that diffusional effects could be analyzed and quantified. This allowed the calculation of rate coefficients for the oxidation reaction. These rate coefficients were then used in a kinetic model of the four-ball wear tester to predict film thickness in concentrated contacts. Presented at the 38th Annual Meeting in Houston, Texas, April 24–28, 1983
TL;DR: In this article, an analytic study of the effects of phase change on load support for parallel and tapered face seals is presented, considering an adiabatic model for low Reynolds number flow.
Abstract: An analytic study is presented of the effects of phase change on load support for parallel and tapered face seals. Consideration is given to an adiabatic model for low Reynolds number flow. Numerical integration is carried out of the descriptive fluid equations, giving the opening force due to fluid film pressure. The loci of steady-state solutions are then plotted for water to provide curves of load support as a function of film thickness. For axial excursions of the seal rings, a quasi-steady transient analysis is made. It is found that the load support generated by fluid pressure can be multivalued for a given film thickness. Another finding is that axial disturbances of the seal rings may lead to sudden drops in load support generated by fluid pressure with three possible results. The first is that sufficient damping may permit the seal to return to the previous equilibrium operating position. The second is that the seal may collapse to an equilibrium position of smaller film thickness where face contact is more likely and a significantly higher operating temperature is assured. The third is that a limit cycle of self-sustained oscillation in the axial direction may occur if damping is sufficiently low.