IN-SITU DETERMINATION OF THE THERMO-PHYSICAL PROPERTIES OF NANO-PARTICULATE LAYERS DEVELOPED IN ENGINE EXHAUST GAS HEAT EXCHANGERS AND OPPORTUNITES FOR HEAT EXCHANGER EFFECTIVENESS RECOVERY by Ashwin Ashok Salvi A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Mechanical Engineering) in The University of Michigan 2013 Doctoral Committee: Dionissios N. Assanis, Co-Chair Professor Claus Borgnakke, Co-Chair Associate Research Scientist John W. Hoard, Co-Chair Professor Arvind Atreya Professor John W. Barker Daniel J. Styles, Ford Motor Company Ashwin Ashok Salvi © 2013 All Rights Reserved To my parents Dr. Ashok Salvi and Dr. Usha Salvi ii ACKNOWLEDGMENTS I would like to start off by acknowledging my advisors Dr. Dennis Assanis and John Hoard. Dr. Assanis, you inspired me to pursue my graduate studies in the Walter E. Lay Automotive laboratory after taking your Internal Combustion Engines course. You have always supported me from the beginning of my Master’s and all the way throughout my Ph.D. Your enthusiasm and passion for science is truly contagious and your desire to see your students succeed has kept me going throughout my graduate career. Thank you for everything. John, your mentorship and advice has been invaluable to me. I have thoroughly enjoyed our scientific and worldly conversations and admire not only your curiosity for all things research, but also philosophical. Thank you for giving me the opportunity to work with and learn from you. A sincere thank you to my committee members: Dan Styles, Dr. Claus Borgnakke, Dr. John Barker, and Dr. Arvind Atreya. Dan, thank you for giving me the opportunity to contribute to Ford research. Your ability to assimilate and distill information makes you a great leader and your thoughts and advice on this project have been instrumental to its success. Thank you for all the financial and more importantly intellectual support from Ford Motor Company. Dr. Borgnakke, thank you for all of the conversations related to my research and to the field of science in general. It has been a pleasure exchanging ideas and information with you and partaking in numerous lab tours with you. Dr. Barker, thank you for joining my committee. Thank you for opening my eyes to the world of atmospheric chemistry. AOSS 578 still ranks amongst the top of my all-time favorite classes. Dr. Atreya, thank you for teaching me about advanced heat iii transfer. It was a subject that was very helpful in my research and helped me to make sense of my work. Thank you to Scott Sluder, Michael Lance, and John Storey from Oak Ridge National labs for their thoughts and advice. Thank you Dr. Lance for performing thermogravimetric analysis on our deposit samples. There are far too many people that I am grateful for. Dr. Mehdi Abarham, thank you so much for all of your help. My research truly would not have been possible without you. Mitchell Bieniek, Kevin Collao, Theerapat Yangyuenthanasan, Pavan Jagarlapudi, Rajagopal Jayaraman – thank you for all your help in the lab. You are all truly exceptional students. Dr. Rajit Johri and Dr. Fernando Tavares, thank you guys for all the support throughout these years and for all the great conversations. Dr. Mark Hoffman, I enjoyed all of our scientific and non-scientific conversations alike. Dr. Josh Lacey, Dr. Anne Marie Lewis, Dr. Ben Lawler, Luke Hagen, Dr. Michael Mosburger, Dr. Michael Cundy, Jerry Fuschetto, Kevin Zaseck, Louise Lu, Dr. Brian Peterson, Dr. Karl Zelik, Dr. Jonathan Hagena, Dr. Bruno Vanzieleghem, Dr. Tulga Ersal, William Lim, Melissa McGeorge, Kathie Wolney, Laurie Stoianowski, Kent Pruss, Bill Kirkpatrick, and everybody else in the autolab – thank you for making the past few years such a fond memory. I truly believe the students, former and current, make this lab one of the most unique, social, intellectual, and passionate labs on campus. Thanks for all the support and good times. Thanks to all my family and friends for the years of unconditional support. Special thanks to Dr. Ajay Jetley, Andrea Callas, Dr. Amar Desai, and Dr. Keshav Deshpande for their friendship. Thanks especially to my parents, Dr. Ashok Salvi and Dr. Usha Salvi, who have always been there for me. I am incredibly fortunate to have you in my life. You guys are my inspiration, role models, moral compass, and foundation. Thank you for all your sacrifice. I would not be the person I am today without you. Always and forever GO BLUE! iv TABLE OF CONTENTS DEDICATION....................................................................................................... ii ACKNOWLEDGMENTS ................................................................................... iii LIST OF FIGURES .............................................................................................. x LIST OF TABLES ............................................................................................. xxi LIST OF ABBREVIATIONS .......................................................................... xxii ABSTRACT ...................................................................................................... xxiv CHAPTER 1 INTRODUCTION ......................................................................... 1 1.1 EGR Cooler Fouling ..................................................................................... 2 1.2 Deposits ...................................................................................................... 12 1.2.1 What are deposits ................................................................................ 12 1.2.2 Properties of deposits .......................................................................... 17 1.3 Deposition mechanisms .............................................................................. 24 1.4 Stabilization and recovery .......................................................................... 26 1.5 Models ........................................................................................................ 31 1.6 References .................................................................................................. 38 CHAPTER 2 MEASUREMENT PRINCIPLE AND EXPERIMENTAL EQUIPMENT ...................................................................................................... 42 2.1 Measurement Principle ............................................................................... 42 2.2 Experimental hardware ............................................................................... 45 2.2.1 Visualization rig .................................................................................. 45 2.2.2 Infrared camera ................................................................................... 49 2.2.3 Infrared and optically transmissible window ...................................... 53 2.2.4 Microscope .......................................................................................... 55 2.2.5 Heat flux probe ................................................................................... 55 v 2.2.6 Diesel engine ....................................................................................... 57 2.2.7 Gaseous emissions analyzer ................................................................ 59 2.2.8 Particulate analyzers ........................................................................... 61 2.3 References .................................................................................................. 64 CHAPTER 3 EXPERIMENTAL IN-SITU METHODOLOGY .................... 65 3.1 Reflected temperature ................................................................................. 65 3.2 Deposit layer emissivity ............................................................................. 67 3.2.1 Isothermal experiment ........................................................................ 68 3.3 Infrared window ......................................................................................... 70 3.3.1 Transmissivity ..................................................................................... 70 3.3.2 Infrared camera angle ......................................................................... 73 3.4 Deposit layer transparency ......................................................................... 75 3.5 References .................................................................................................. 82 CHAPTER 4 DEPOSIT LAYER EVOLUTION ON STAINLESS STEEL SUBSTRATE ....................................................................................................... 83 4.1 Experimental conditions ............................................................................. 83 4.1.1 Engine conditions................................................................................ 84 4.1.2 Exhaust gas composition..................................................................... 88 4.2 24-hour deposition experimental results .................................................... 95 4.2.1 Deposit layer thickness ....................................................................... 95 4.2.2 Deposit layer topography and surface area ......................................... 97 4.2.3 Infrared surface temperature ............................................................. 104 4.3 Conclusions .............................................................................................. 110 4.4 References ................................................................................................ 112