"Doctoral thesis accepted by the University of Sheffield, UK."

SpringerLink Springer Engineering eBooks 2017 English+International

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Supervisor's Foreword; Contents; Nomenclature; Introduction; Thesis Layout; Summary; 1 Introduction; 1.1 Statement of the Problem; 1.2 Project Aims; 1.3 Thesis Layout; References; 2 Background on Viscosity and Lubrication; 2.1 Definition of Viscosity; 2.1.1 Viscosity Relation with Temperature; 2.1.2 Viscosity Index; 2.1.3 Viscosity and Pressure; 2.1.4 Viscosity and Shear Rate; 2.2 Viscosity Measurement; 2.2.1 Capillary Viscometers; 2.2.2 Rotational Viscometers; 2.2.3 Falling Body Viscometers; 2.2.4 Vibrational Viscometers; 2.2.5 High Pressure Viscometers; 2.2.6 High Shear Viscometers.

2.3 Engine Lubricating Oil Composition2.3.1 Base Oils; 2.3.2 Viscosity Modifiers; 2.3.3 Detergents; 2.4 Oil Classification by Viscosity; 2.5 Lubrication Principles in Mechanical Components; 2.5.1 The Stribeck Curve; 2.5.2 Journal Bearing Lubrication; 2.5.3 Considerations for Journal Bearing Design; 2.6 Conclusions; References; 3 Background on Ultrasound; 3.1 Introduction to Ultrasound; 3.2 Ultrasound and Material Properties; 3.3 Ultrasonic Transducers; 3.3.1 The Piezoelectric Effect; 3.3.2 Ultrasonic Transducer Type; 3.3.3 Other Type of Ultrasonic Transducers.

3.4 Characteristics of Ultrasonic Signals3.5 Transducers Arrangements; 3.6 Reflection of Ultrasound Waves at Interface; 3.6.1 Reflection and Transmission in a Three-Layered System; 3.6.2 Reflection of Shear Waves at Solid-Liquid Boundary; 3.7 Conclusions; References; 4 Literature Review; 4.1 The Crystal Resonator; 4.2 The Resonating Plate/Rod; 4.3 Reflectance Methodologies; 4.3.1 The Newtonian Reflection Model; 4.3.2 The Greenwood Model; 4.4 The Attenuation Method; 4.4.1 Ultrasonic Spectroscopy Methods; 4.5 Ultrasonic Resonator to Analyse Lubricating Oils.

4.6 Comparison of Ultrasonic Viscometers and Conventional Viscometers4.7 Conclusions; References; 5 A Novel Ultrasonic Model for Non-Newtonian Fluids; 5.1 Introduction; 5.2 The Maxwell Fluid Model; 5.3 The Ultrasonic Model for Non-Newtonian Fluids; 5.4 Comparison of Models; 5.5 Non-Newtonian Ultrasonic Model Sensitivity Analysis; 5.5.1 Reflection Coefficient; 5.5.2 Fluid Density; 5.5.3 Solid Density; 5.6 Conclusions; References; 6 Viscosity Measurements at an Aluminium-Oil Boundary; 6.1 Ultrasonic Apparatus; 6.1.1 The Transducers; 6.1.2 The Cables; 6.1.3 Thermocouple Calibration.

6.1.4 Test Lubricants6.1.5 Experimental Protocol; 6.2 Signal Processing; 6.3 Conventional Reflectance Technique: Results; 6.4 Conventional Reflectance Technique: Acoustic Mismatch; 6.5 Conclusions; References; 7 The Matching Layer Method; 7.1 Origins of the Matching Layer Methodology; 7.2 Matching Layer Theory; 7.3 Measurement Apparatus; 7.3.1 Instrumentation; 7.3.2 Test Cell and Matching Layer; 7.3.3 Samples Tested; 7.4 Signal Processing and Data Analysis; 7.5 Results; 7.5.1 Measurement Sensitivity Increment; 7.5.2 Viscosity Results for Newtonian Oils.

This thesis presents a novel ultrasonic instrument for non-invasive and in-situ characterization of journal bearing lubricant viscosity. In particular, the application to journal bearings is described by non-invasively measuring the viscosity and localized power losses throughout operation. This ultrasonic viscometer is based on the reflection of polarized shear waves from a thin resonating coating layer to increase the measurement sensitivity, in comparison to conventional ultrasonic methods. This instrument allows for a full engine oil viscoelastic characterization in-situ. The book investigates the effects of temperature, pressure and shear rate, and describes in detail the ultrasonic setup and method. Further, it demonstrates that the same technique can be applied similarly to monitor the lubrication of other engine components. As such, it offers a unique instrument that can drive the research of oil formulations to improve engine performance and fulfill the requirements of international fuel economy regulations.