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Conformal & Non-Conformal Surfaces. Figure 1.1 Conformal Surfaces. [From Hamrock and Anderson (1983).]. Figure 1.2 Nonconformal Surfaces. [From Hamrock and Anderson (1983).]. Hydrodynamic Lubrication. Minimum film thickness:. Figure 1.3 Characteristics of hydrodynamic lubrication. - PowerPoint PPT Presentation
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Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Conformal & Non-Conformal Surfaces
Figure 1.1 Conformal Surfaces. [From Hamrock and Anderson (1983).]
Figure 1.2 Nonconformal Surfaces. [From Hamrock and Anderson (1983).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Hydrodynamic Lubrication
Figure 1.3 Characteristics of hydrodynamic lubrication.
Minimum film thickness:
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Pressure Development
Figure 1.4 Mechanisms of pressure development for hydrodynamic lubrication. (a) Slider bearing; (b) squeeze film bearing; (c) externally pressurized bearing.}
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Elastohydrodynamic Lubrication
Figure 1.5 Characteristics of hard elastohydrodynamic lubrication
Figure 1.6 Characteristics of soft elastohydrodynamic lubrication
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Regimes of Lubrication
Figure 1.5 Film conditions of lubrication regimes. (a) Fluid film lubrication - surfaces separated by a bulk lubricant film; (b) partial lubrication - both bulk lubricant and boundary film play a role; (c) boundary lubrication - performance depends entirely on boundary film.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Friction for Various Lubrication Conditions
Figure 1.8 Bar diagram showing friction coefficient for various lubrication conditions.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Wear Rates for Lubrication Regimes
Figure 1.9 Wear rates for various lubrication regimes.
[From Beerbower (1972)].
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Boundary Lubricants
Table 1.1 Fatty acids in oil as lubricants. [From Dorinson and Ludema (1985).]
Figure 1.10 Effect of chain length on the effectiveness of a boundary lubricant. (a) Critical temperature as a function of chain length [From Bowden and Tabor (1950)]; (b) friction coefficient as a function of chain length. [From Zisman (1959).]}
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Langmuir-Blodgett Films
Figure 1.11 Effect of boundary lubricant thickness on friction for Langmuir-Blodgett films. [From Bowden and Tabor (1950).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Boundary Lubricant Mechanisms
Figure 1.12 Physisorption of of n-hexadecane molecules to a metal surface. [From Ku (1970).]
Figure 1.12 Chemisorption of stearic acid to an iron-containing surface to form iron stearate. [From Ku (1970)]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Boundary Lubrication Mechanisms (cont.)
Figure 1.15 Thermal activation of a boundary lubricant during the initial thermal cycle.
Figure 1.14 Formation of sulfide layers on steel, an example of boundary lubrication through chemical reactions involving the substrate.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Stribeck Curve
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Bearing Classification
Figure 2.1 Divisions of conformal fluid film bearings. Figure 2.2 Divisions of
rolling-element bearings.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Guide to Journal
Bearings
Figure 1.5 General guide to journal bearing type. Except for rolling-element bearings, curves are drawn for bearings with width equal to diameter. A medium-viscosity mineral oil is assumed for hydrodynamic bearings. [From ESDU (1965).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Guide to Thrust
Bearings
Figure 2.4 General guide to thrust bearing type. Except
for rolling-element bearings, curves are drawn for typical ratios of inside diameter to
outside diameter. A medium-viscosity mineral oil is
assumed for hydrodynamic bearings. [From ESDU
(1967).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Surface Profiles
Figure 3.2 Difficulty in interpreting profilometer traces. (a) Surface profile; (b) surface asperity.
Figure 3.1 Geometric characteristics of solid surfaces [From Halling (1976).]
Figure 3.3 Error due to stylus radius.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Compressed Surface Profile
Figure 1.5 True (a) and compressed (b) profile. [From Thomas (1982).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Atomic Force Microscope
Figure 3.5 Schematic illustration of an atomic force microscope. (a) Principle of operation for an AFM. (b) Typical cantilevers for use in an atomic force microscope. [Source: Digital Instruments Corp.]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Devices for Surface Measurement
Table 3.1 Summary of typical specifications of devices used for surface topography measurement. [From Sherrington and Smith (1988)].
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Reference Lines
Figure 3.6 Comparison of three types of reference line: (a) M system; (b) ten-point average; (c) least squares.
Mean or M System: Areas above and below the horizontal line are equal.
Ten-point average: Use five highest peaks and five lowest valleys
Least Squares: Similar to M System, but line can be inclined.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Roughness Issues
Figure 3.7 Geometric profiles having same values of arithmetic average. [From Halling (1976).]
Roughness measures:
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Typical Roughness
Table 3.2 Typical arithmetic averages for various processes and components.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Bearing Area Curve
Figure 3.8 Surface profile showing bearing length. [From Persson (1992).]
Figure 3.9 Abbot curves for two different profiles. [From Persson (1992).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
All-Ordinate Distribution
Figure 3.10 Method of deriving all-ordinate distribution. [From Halling (1975).]
Gaussian distribution:
Roughness measures:
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Skewness and Kurtosis
Figure 3.11 Illustration of three different kurtosis values. [From Halling (1975).]
Skewness:
Kurtosis:
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Autocorrelation Parameter
Figure 3.12 Two different surfaces and resulting autocorrelation functions. (a) Periodicity profile; (b) decay profile. [From Halling (1975).]
Autocorrelation:
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Friction vs. Film Parameter
Figure 3.13 Variation of friction coefficient with film parameter. [From Hamrock and Dowson (1981).]
Film parameter:
Friction coefficients:
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Paraffins
Table 4.2 Homologous series of hydrocarbons. [From Hess (1981).]
Table 4.1 Straight-chain paraffins [From Pugh (1970)].
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Petroleum Products
Table 4.3 Petroleum products with boiling point range and number of carbon atoms present.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Lubricant Formulas
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Synthetic Lubricants
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Poly-Alpha-Olefin (PAO)
Figure 1.5 Poly-alpha-olefin (PAO) structures. The “star” orientation displays superior lubrication properties. [From Kioupis and Maginn (1999).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Greases
Table 4.7 Typical characteristics of lubricating greases.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Fluid Viscosities
Figure 4.2 Absolute viscosities of a number of fluids for a wide range of temperatures.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Viscosity of Gases
Figure 4.3 Viscosity of common gases as a function of temperature. [From Cameron (1976).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Viscosity of Gases
Table 4.8 Viscosity of various gases at 14.7 psia. [From Svehla (1962).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Properties of Liquids & Gases
Table 4.9 Some properties of common liquids and gases at 68°F and 14.7 psia. [From Gross (1980).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
EmulsionsTypically 5% oil, 95% water.
Oil phase includes additives including emulsifier.
Emulsifier stabilizes emulsion and determines particle size.
Outstanding cooling properties and reasonable lubrication effectiveness.
Figure 4.4 An oil-in-water emulsion stabilized by an emulsifier.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Newtonian Fluids
Figure 4.5 Properties of a Newtonian fluid. (a) Effect of viscosity on shear strain rate; (b) effect of shear stress on shear strain rate.
Figure 4.6 Physical illustration of Newton's postulate, where f = friction force, N; A = area, m2; u=velocity, m/s; h = film thickness, m.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Viscosity Conversion Factors
Table 4.10 Viscosity conversion factors.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Kinematic Viscosity
Table 4.10 Divergence between kinematic and absolute viscosity data with increasing temperature. [From Klaman (1984).]
Kinematic viscosity:
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Viscosity Grades
Figure 1.5 Viscosity grade comparisons. [From Litt (1986).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Viscosity-Pressure Effects
Table 4.12 Absolute and kinematic viscosities of fluids at atmospheric pressure and three temperatures. [From Jones et al. (1975).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Roelands & Barus
EquationsBarus Law:
Roelands (isothermal):
Figure 4.8 Comparison of absolute viscosity obtained from Barus' and Roelands' formulas for a wide range of pressure. Results are shown for three different lubricants at 38°C; oil 1 --- synthetic paraffinic oil (lot 3); oil 2 --- superrefined napthenic mineral oil; oil 3 --- synthetic hydrocarbon (traction fluid).
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Fluid Designations
Table 4.13 Fluids with manufacturer and manufacturer’s designation. [From Jones et al. (1975).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Pressure-Viscosity Coefficients
Table 4.14 Pressure-viscosity coefficients for fluids at three temperatures. [From Jones et al. (1975).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Piezo-viscous and Thermo-viscous Behavior
Figure 4.9 Absolute viscosities of SAE lubricating oils at
atmospheric pressure.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Thermal Properties of Liquids
Table 4.16 Typical thermal properties of some liquids.
[From Winer and Cheng (1980).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Viscosity-Shear Rate Effects
Figure 4.10 Characteristics of different fluids as a function of shear rate. (a) Viscosity; (b) shear stress.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Viscosity Index
Figure 4.11 Graphical explanation of viscosity index where L = low VI oil, x = unknown oil, and H=high VI oil.)
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Viscosity Index Data
Table 4.17 Viscosity-index data to be used in Eq. (4.18). [From: An
abridgement from ASTM D567, ``Standard Method for Calculating Viscosity Index''.]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
VI Improver Molecules
Figure 4.12 Summary of common viscosity index improver molecules.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Properties of Base Fluids
TAble 4.18 Base fluids tested, with corresponding kinematic viscosity and average molecular weight. [From Hamrock et al. (1987).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Compressibility
Figure 4.13 Effect of pressure on relative volume for six base fluids. Constant
temperature of 20°C assumed. [From Hamrock et al. (1987).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Compressibility
Figure 4.14 Effect of pressure on density. [From Hamrock et al. (1987).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Limiting Shear Stress
Figure 4.15 Comparison of rheological models for isothermal conditions.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Non-Newtonian Rheology
Figure 4.16 Non-Newtonian rheological models represented by (a) effect of shear strain rate on dimensionless shear stress and (b) effect of dimensionless shear stress on dimensionless effective viscosity. [From Myllerup et al. (1993).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Effective Viscosity
Figure 4.16 Non-Newtonian rheological models represented by (a) effect of shear strain rate on dimensionless shear stress and (b) effect of dimensionless shear stress on dimensionless effective viscosity. [From Myllerup et al. (1993).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Conformal Bearing Materials
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
White Metal Bearing Alloys
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Alloys in General Use
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Bronze & Copper Bearing Alloys
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Non-Metallic Bearing Materials
Figure 5.1 Phenolic laminate bearings. (a) Tubular bearing; (b) circumferentially laminated bearing; (c) axially laminated bearing; (d) stave
bearing; (e) molded bearing. [From Kaufman (1980).]
Table 5.5 Limits of application of nonmetallic bearing materials. [Revised from O'Connor et al. (1968)].
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Phenolic Bearing Applications
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Bearing Surfaces
Figure 5.2 Different forms of bearing surfaces. (a) Solid bearing; (b) lined bearing; (c) filled bearing; (d) shrink-fit bearing.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Bearing Steels
Figure 5.3 Hot hardness of CBS 1000, CBS 1000M, Vasco X-2, and high-speed tool steels. [From
Anderson and Zaretsky (1975).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Density
Table 5.8 Densities of various metals, polymers, and ceramics at room temperature (20°C; 68°F) [From ESDU (1984).]
Figure 5.4 Illustration of density for various metals, polymers, and ceramics at room temperature (20°C; 68°F). [From ESDU (1984).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Elastic Modulus
Figure 5.5 Modulus of elasticity for various metals, polymers, and ceramics at room temperature (20°C; 68°F) [From ESDU (1984).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Poisson’s Ratio
Table 5.10 Poisson's ratio for various metals, polymers, and ceramics at room temperature (20°C; 68°F) [From ESDU (1984).]}
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Thermal Expansion Coefficient
Figure 5.6 Illustration of thermal expansion coefficient for various metals, polymers, and ceramics applied over temperature range 20 to 200°C (68 to 392°F). [From ESDU (1984).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Thermal Conductivity
Figure 5.7 Illustration of thermal conductivity for various metals, polymers, and ceramics. [From ESDU (1984).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Specific Heat Capacity
Figure 5.8 Illustration of specific heat capacity for various metals, polymers, and ceramics at room temperature (20°C; 68°F). [From ESDU (1984).]
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Concentric Journal Bearing
Figure 6.2 Developed journal and bearing surfaces for a concentric journal bearing.Figure 6.1 Concentric Journal Bearing.
Petrov’s Equation:
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Navier-Stokes Equation
Figure 6.3 Stresses on two surfaces of a fluid element.
Cartesian Coordinates:
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Continuity Equation
Figure 6.4 Velocities and densities for mass flow balance through a flux volume element in two dimensions.
Figure 6.5 Flow between parallel flat plates.
Continuity Equation:
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Couette & Poiseuille Flow
Figure 6.6 (a) Couette and (b) Poiseuille velocity profiles.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Velocity Profiles
Figure 6.7 Some interesting velocity profiles.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Flow Examples
Figure 6.8 Flow in a circular pipe.
Figure 6.9 Flow down a vertical plane.
Fundamentals of Fluid Film LubricationHamrock, Schmid & JacobsonISBN No. 0-8247-5371-2
Viscosimeters
Figure 6.10 Important features of a capillary viscometer.
Figure 6.10 Rotational circular viscometer.
Figure 6.10 Cone-and-plane viscometer.