High Pressure Rheology for Quantitative Elastohydrodynamics (eBook)

Scott S. Bair (Autor)

eBook Download: PDF

2007 | 1. Auflage
260 Seiten
Elsevier Science (Verlag)
978-0-08-047530-1 (ISBN)

Infos

Computational elastohydrodynamics, a part of tribology, has existed happily enough for about fifty years without the use of accurate models for the rheology of the liquids used as lubricants. For low molecular weight liquids, such as low viscosity mineral oils, it has been possible to calculate, with precision, the film thickness in a concentrated contact provided that the pressure and temperature are relatively low, even when the pressure variation of viscosity is not accurately modelled in detail. Other successes have been more qualitative in nature, using effective properties which come from the fitting of parameters used in calculations to experimental measurements of the contact behaviour, friction or film thickness.
High Pressure Rheology for Quantitative Elastohydrodynamics is intended to provide a sufficiently accurate framework for the rheology of liquids at elevated pressure that it may be possible for computational elastohydrodynamics to discover the relationships between the behaviour of a lubricated concentrated contact and the measurable properties of the liquid lubricant. The required high-pressure measurement techniques are revealed in detail and data are presented for chemically well-defined liquids that may be used as quantitative reference materials.
* Presents the property relations required for a quantitative calculation of the tribological behaviour of lubricated concentrated contacts.
* Details of high-pressure experimental techniques.
* Complete description of the pressure and temperature dependence of viscosity for high pressures.
* Some little-known limitations on EHL modelling.

Inhalt

Cover 1
Copyright page 5
Table of Contents 6
Preface 10
Nomenclature 12
Figure Credits 18
Acknowledgements 20
Chapter 1. An Introduction to Elastohydrodynamic Lubrication 22
1.1 Lubrication 22
1.2 Concentrated Contact Lubrication 23
1.3 Full Elastohydrodynamic Lubrication 28
1.4 Experimental Elastohydrodynamics 30
1.5 Conclusion 34
References 35
Chapter 2. An Introduction to the Rheology of Polymeric Liquids 36
2.1 Background 36
2.2 The Newtonian Model 37
2.3 Material Functions for Polymeric Liquids 39
2.4 Rheological Models 44
2.5 Time–Temperature–Pressure Superposition 51
2.6 Liquid Failure 53
References 53
Chapter 3. General High-Pressure Experimental Technique 56
3.1 Background 56
3.2 Pressure Containment 57
3.3 Closures 60
3.4 Feed-Throughs 63
3.5 Pressure Generation and Measurement 68
3.6 Hydrostatic Media and Volume Compensation 72
References 74
Chapter 4. Compressibility and the Equation of State 75
4.1 Background 75
4.2 PVT Measurement Techniques and Results 76
4.3 Empirical Equations of States 88
References 92
Chapter 5. The Pressure and Temperature Dependence of the Low-Shear Viscosity 94
5.1 Background 94
5.2 Viscometers for High Pressure 96
5.3 General Pressure–Viscosity Response and Results for Pure Organic Liquids and Lubricants 108
References 119
Chapter 6. Models for the Temperature and Pressure Dependence of Low-Shear Viscosity 122
6.1 Introduction 122
6.2 Models for the Temperature–Viscosity Response 123
6.3 Fragility and Empirical Models for High Pressure Behavior 125
6.4 The Pressure–Viscosity Coefficient and Empirical Models for Low Pressure Behavior 128
6.5 Empirical Models for Large Pressure Intervals 134
6.6 Models Based on Free Volume Theory 137
6.7 Generalized Temperature–Pressure–Viscosity Models 143
6.8 Multi-Component Systems 145
References 150
Chapter 7. Measurement Techniques for the Shear Dependence of Viscosity at Elevated Pressure 154
7.1 Introduction 154
7.2 Phenomena Producing Behavior Similar to Shear-Thinning 157
7.3 Rheometers for High Pressure 163
References 178
Chapter 8. The Shear Dependence of Viscosity at Elevated Pressure 181
8.1 Introduction 181
8.2 Normal Stress Differences at Elevated Pressures 184
8.3 The Origin of Non-Newtonian Behavior in Low-Molecular-Weight Liquids at Elevated Pressures 187
8.4 Time–Temperature–Pressure Superposition 192
8.5 The Competition between Thermal Softening and Shear-Thinning 195
8.6 Multi-Component Systems 196
8.7 The Power-Law Exponent and the Second Newtonian Viscosity 198
References 200
Chapter 9. The Glass Transition and Related Transitions in Liquids Under Pressure 204
9.1 Measurements of Glass Transition at Elevated Pressure 204
9.2 Measurements of Dielectric Transition at Elevated Pressure 207
9.3 The Transitions as Isoviscous States 209
9.4 The Pressure Variation of Viscosity across the Transition 211
References 212
Chapter 10. Shear Localization, Slip and the Limiting Stress 214
10.1 Introduction 214
10.2 Measurements of Rate Independent Shear Stress 216
10.3 Flow Visualization of Shear Bands 218
10.4 Mohr–Coulomb Failure Criterion 221
10.5 Change of Character of the Piezoviscous Navier–Stokes Equations 223
10.6 Thermal Localization, Adiabatic Shear Bands 224
10.7 Interfacial Slip 225
References 225
Chapter 11. The Reynolds Equation 227
11.1 Background 227
11.2 Reynolds Equations for Generalized Newtonian Fluids 230
References 237
Chapter 12. Applications to Elastohydrodynamics 239
12.1 Introduction 239
12.2 Film Thickness for Shear-Thinning Liquids 241
12.3 The Calculation of Traction from Material Properties 248
References 257
Index 259

Produkt-Details

• Erscheint lt. Verlag: 6.3.2007
• Sprache: englisch
• Themenwelt: Sachbuch/Ratgeber
• Themenwelt: Naturwissenschaften ► Chemie
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Strömungsmechanik
• Themenwelt: Technik ► Bauwesen
• Themenwelt: Technik ► Maschinenbau
• Themenwelt: Technik ► Umwelttechnik / Biotechnologie
• ISBN-10: 0-08-047530-2 / 0080475302
• ISBN-13: 978-0-08-047530-1 / 9780080475301