Measurement of Dynamic Characteristics of a Herringbone-grooved Hydrodynamic Journal Bearing with Different Operating Parameters

The concept of herringbone-grooved hydrodynamic journal bearing has been quite mature while the real application still has large room for improvement. The fluid-film force in a herringbone-grooved bearing can be treated as a set of linear stiffness and damping coefficients. These dynamic coefficients represent the dynamic characteristics of a hydrodynamic bearing. This thesis presents an experimental apparatus and method to obtain the dynamic coefficients of a herringbone-grooved hydrodynamic bearing with different operating parameters. The effects of different operating parameters are discussed in this thesis.Chapter 1 Introduction 15.1. General Remarks 15.2. Motivation and Objectives 17.3. Literature Survey 18.4. Thesis Organization 20hapter 2 Theory of Lubrication and Rotating System 27.1. Petroff’s Equation and Sommerfeld number 27.2. Dynamics of a Rotor-Bearing System with Fluid Film 29.2.1. Motion of a Rotor with Fluid Film 29.2.2. Fluid Film Forces and Dynamic Coefficients 31.3. Method of Measurement of Dynamic Coefficients of Fluid-Film of Hydrodynamic Journal Bearing 33.3.1. Static-Load Method for Measuring Stiffness of Lubricant Film 33.3.2. Centrifugal Forces by Using Imbalance Mass for Measuring Damping Coefficients 35.4. Analysis of the Stability of Hydrodynamic Journal Bearing 37.4.1. Attitude Angle 37.4.2. Critical Mass and Critical Frequency 38hapter 3 Fabrication of the Experimental Equipments and Procedures 44.1. Design of Herringbone Microgrooves and Fabrication of Hydrodynamic Journal Bearing 44.2. Fabrication of the Experiment Fan 46.3. Balance of the rotor 47.4. Fabrication of the Experimental System 49.5. Experimental Procedures for the Measurement of Dynamic Characteristics 53hapter 4 Results and Discussion 80.1. Effects of Loadings on the Motion of the Rotor and on the Dynamic Coefficients 80.1.1. Loci of the Shaft, Orbit of the Mass of Center and Eccentricity Ratio with Respect to Loading 80.1.2. Loading Effect on the Stiffness and Damping Coefficients 82.2. Verification of Experimental Method 83.2.1. Nondimensional Analysis and Comparison with the Prior Studies 83.2.2. Verification of the Method for Measurements and Calculations 86.3. Effects of Rotating Speed 87.4. Effects of Dynamic Viscosity 89.5. Effects of Imbalance 90.6. Stability Analysis 91hapter 5 Conclusions and Future Prospects 113eferences 11