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The Detection of Journal Bearing Cavitation with Use of Ultrasound THE DETECTION OF JOURNAL BEARING CAVITATION WITH USE OF ULTRASOUND TECHNOLOGY By GREGORIO MIRANDA Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science Department of Mechanical Engineering CASE WESTERN RESERVE UNIVERSITY May 2016 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis of Gregorio Miranda Candidate for the degree of Master of Science Committee Chair Dr. Joseph M. Prahl Committee Member Dr. Paul Barnhart Committee Member Dr. Roger D. Quinn Date of Defense April 4, 2016 We also certify that written approval has been obtained for any proprietary material contained therein. ii TABLE OF CONTENTS TABLE OF CONTENTS……………………………………………………………………....III LIST OF TABLES…………………………………………………………………………….....V LIST OF FIGURES…………………………………………………………………………….VI ABBREVIATIONS…………………………………………………………………………….IX LIST OF SYMBOLS…………………………………………………………………………….X ACKNOWLEDGEMENTS……………………………………………………………….....XIV ABSTRACT…..………………………………………………………………………………..XV CHAPTER I. INTRODUCTION…………………………………………………………………...1 II. REVIEW OF LITERATURE……………………………………………………….6 2.1 CAVITATION, THE PHYSICAL PHENOMENA……………………………….6 2.1.1 Definition…………………………………………………………………………..6 2.1.2 Vapor Pressure …………………………………………………………………...7 2.1.3 Main Forms of Vapor Cavities ……………………………………………...…..9 2.2 PHASE CHANGE, NUCLEATION, & CAVITATION…………………………14 2.2.1 Liquid State……………………………………………………………………....14 2.2.2 Tensile Strength …………………………………………………………………15 2.2.3 Cavitation & Boiling……………………………………………………………16 2.2.4 Nucleation……………………………………………………………………..…17 2.2.5 Cavitation Number………………………………………………………………19 2.2.6 Inception of Cavitation………………………………………………………….20 2.3 CAVITATION IN LIQUID FLOWS…………………………………………….22 2.3.1 Cavitation Regimes……………………………………………………………...22 2.3.2 Favorable Situations that Yield Cavitation…………………………………..23 2.3.3 Effects of Cavitation…………………………………………………………….24 2.3.4 Existence in Automotive Plain Bearings……………………………………..25 2.4 HYDRODYNAMIC BEARINGS……………………………………………….26 2.4.1 Introduction……………………………………………………………………...26 2.4.2 Definition of Terms……………………………………………………………...26 2.4.3 Fundamental Theory of Operation……………………………………………28 2.4.4 Cavitation in Journal Bearings………………………………………………..36 iii III. NUMERICAL SETUP & PROCEDURES………………………………………..39 3.1 INTRODUCTION…………………………………………………………….....39 3.2 DERIVATION OF REYNOLDS EQUATION………………………………….39 3.2.1 Reynolds Equation……………………………………………………………....39 3.2.2 Cavitation Model………………………………………………………………..44 3.3 NUMERICAL IMPLEMENTATION & DISCRETIZATION…………………..47 3.4 PREDICTED CAVITATION REGION IN BEARING DESIGN……………….53 IV. EXPERIMENTAL SETUP & PROCEDURES………………...…………………54 4.1 INTRODUCTION…………………………...…………………………………..54 4.2 JOURNAL BEARING TEST BENCH DESIGN………………………………...55 4.2.1 Bearing Design…………………………………………………………………..55 4.2.2 Overview of Test Apparatus……………………………………………………58 4.2.3 Bearing Load Application.……………………………………………...……...61 4.2.4 Lubrication System…………………………………………………...…………62 4.2.5 Data Acquisition & Control……………………………………………………64 4.3 APPLICATION OF ULTRASOUND TECHNOLOGY…………………...……65 4.3.1 Introduction…………………………………………………………………...…65 4.3.2 Theory of Operation……………....………………………………………….…66 4.3.3 Setup & Application………………………………………………………….….69 4.3.4 Data Acquisition and Signal Processing……………………………………..70 4.3.5 Pulsing Settings………………………………………………………………….72 4.3.6 Testing Procedure……………………………………………………………….72 V. RESULTS………………………………………………………………..…………79 5.1 INTRODUCTION……………………………………………...………………..79 5.2 EXPERIMENTAL RESULTS…………………………………………………...79 VI. CONCLUSIONS & RECOMMENDATIONS………………………………..…..87 APPENDICES………………………………...………………………………………………...92 APPENDIX A………………………………………………………………………...…………93 APPENDIX B……………………………………………………………………………...…..105 APPENDIX C………………………………………………………………………………….109 APPENDIX D……………………………………………………………………………...…..116 BIBLIOGRAPHY…………………………………………………………………………......125 iv LIST OF TABLES Table 2.1 Formulae for determining pressurized lubricant flow in typical lubricant feed designs [7][10]…………………………………………………………………………………………………….…34 Table 3.1 Reynolds simplifying assumptions……………………………………………………….…..40 Table 3.2 Source code inputs……………………………………………………………………………..53 Table 3.3 Source code outputs…………………………………………………………………….……..53 Table 4.1 Bearing housing and journal design geometries……………………………………….….55 Table 4.2 Bearing housing and journal surface finish, material, and material hardness specifications…………………………………………………………………………………………….....56 Table 4.3 Test bench recorded and controlled parameters…………………………………….…….64 Table 4.4 Tribosonics Ltd UPR pulsing configuration…………………………………………….….72 Table 4.5 Test lubricant specifications…………………………………………………………….……76 Table 4.6a Summary of test bench ultrasound data captures (Tests 1-49)………………………....77 Table 4.6b Summary of test bench ultrasound data captures (Tests 49-96)…………………….….78 Table 5.1 Ultrasound DAC channel gain and offset values for RMS voltage determination…………………………………………………………………………………………….…80 v LIST OF FIGURES Figure 2.1 Pressure vs. Temperature Phase Diagram [1]……………………………………………..8 Figure 2.2 Numerical results from Herring and Gilmore’s incompressible analysis; relative cavity Mach number to bubble relative radius [2]…………………………………………………….11 Figure 2.3 Hickling and Plesset pressure distribution before and after cavity collapse [2]………………………………………………………………………………………………………….…12 Figure 2.4 Plesset and Chapman numerical results for bubble collapse velocities near wall [2]…………………………………………………………………………………………………………….13 Figure 2.5 Typical phase diagram [2]……………………………………………………….………….14 Figure 2.6 Modes of heterogeneous nucleation [2]………………………………………….………..19 Figure 2.7 Hydrodynamic bearing………………………………………….…………………….……..27 Figure 2.8 Illustration of the Three Lubrication Regimes [8]………………………………….…....29 Figure 2.9 Principle of hydrodynamic pressure generation between non-parallel surfaces [7]………………………………………………………………………………………………………….…30 Figure 2.10 Load components and pressure field generation in a journal bearing [7]……………………………………………………………………………………………………...…….31 Figure 2.11 Typical lubricant delivery designs [7][10]………………………………………….…..32 Figure 2.12 Table for determining parameters 푓1 and 푓2 for pressurized rectangular lubricant feed grooves [7][10]……………………………………………………………………………………....35 Figure 3.1 Definition of Cartesian coordinates in bearing application……………………….……41 Figure 3.2 Unwrapped bearing subdomain grid point structure………………………………….…48 Figure 3.3 Grid point cluster for unwrapped bearing subdomain grid structure………………....49 Figure 3.4 Pressure distribution for unwrapped hydrodynamic bearing…...……………………...54 Figure 4.1 Fabricated bearing housing……………………………………………………….……..…57 Figure 4.2 Fabricated translucent bearing housing………………………………………….……….58 Figure 4.3 Orthographic rendering of hydrodynamic bearing test bench……………………….…59 Figure 4.4 Rendering of hydrodynamic bearing test bench……………………………………….….59 Figure 4.5 Hydrodynamic bearing test bench…………………………………………………….……60 vi Figure 4.6 Hydrodynamic bearing test bench housing……………………………………….……….61 Figure 4.7 Static load application via pulley and hanging weights………...………………………62 Figure 4.8 Hydrodynamic bearing test bench lubrication system schematic………………………63 Figure 4.9 Sending and receiving ultrasound signals through bearing material………………….67 Figure 4.10 Instrumented bearing housing with ultrasound sensor………………………………...68 Figure 4.11 Final instrumented bearing housing……………………………...………………….…..68 Figure 4.12 Schematic of cavitation detection system…………………………………………….…..70 Figure 4.13 Typical acquired ultrasound signal……………………………………………………....71 Figure 4.14 Measurement of converging and diverging bearing operation with single housing and ultrasound sensor combination……………………………………………………………………..73 Figure 4.15 Journal bearing operation with ultrasound sensor positioned in the diverging region………………………………………………………………………………………………………..74 Figure 4.16 Journal bearing operation with ultrasound sensor positioned in the converging region………………………………………………………………………………………………………..75 Figure 5.1 Measured ultrasound binary raw RMS value standard deviation by measurement region; Converging vs. Diverging ………………..…………………………………………………..…80 Figure 5.2 Measured ultrasound average binary RMS value by region; Converging vs. Diverging……………………………………………………………………………...…………………….81 Figure 5.3 Measured ultrasound average binary RMS value vs. bearing/sensor temperature………………………………………………………………………..…………………….….82 Figure 5.4 Measured ultrasound binary RMS value standard deviation vs. lubricant feed pressure………………………………………………………..…………………………………………….83 Figure 5.5 Measured ultrasound binary RMS value standard deviation vs. lubricant inlet temperature…………………………………………………………………………………………...…….84 Figure 5.6 Measured ultrasound average binary RMS value vs. lubricant feed pressure…………………………………………………………………………………….………….…….85 Figure 5.7 Measured ultrasound average binary RMS value vs. lubricant feed temperature………………………………………………………...……………………………………….86 Figure A-1 Cartesian coordinate system for derivation of Reynolds equation…………………….94 Figure A-2 Equilibrium of single control element in fluid film in x-direction…………………......95 vii Figure A-3 Equilibrium of single control element in fluid film in y-direction...…………………...99 viii ABBREVIATIONS VM Viscosity Modifier PIB Polyisobutylene PMA Polymethacrylate OCP Olefin Copolymer SEMACP Esters of Styrene Maleic Anhydride Copolymer HSDCP Hydrogenated Styrene-diene Copolymer STAR Hydrogenated Radial Polyisoprene OEM Original Equipment Manufacturer UPR Ultrasound Pulser/Reciever
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