Washington University in St. Louis Washington University Open Scholarship Engineering and Applied Science Theses & Dissertations McKelvey School of Engineering Spring 5-15-2020 Ultrafine arP ticle-Particle and Particle-Ion Interactions in Aerosol Reactors Girish Sharma Washington University in St. Louis Follow this and additional works at: https://openscholarship.wustl.edu/eng_etds Part of the Chemical Engineering Commons Recommended Citation Sharma, Girish, "Ultrafine arP ticle-Particle and Particle-Ion Interactions in Aerosol Reactors" (2020). Engineering and Applied Science Theses & Dissertations. 552. https://openscholarship.wustl.edu/eng_etds/552 This Dissertation is brought to you for free and open access by the McKelvey School of Engineering at Washington University Open Scholarship. It has been accepted for inclusion in Engineering and Applied Science Theses & Dissertations by an authorized administrator of Washington University Open Scholarship. 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WASHINGTON UNIVERSITY IN ST LOUIS School of Engineering and Applied Sciences Department of Energy, Environmental, and Chemical Engineering Dissertation Examination Committee: Pratim Biswas, Chair Michel Attoui Richard Axelbaum Peng Bai Rajan Chakrabarty, co-advisor Ultrafine Particle-Particle and Particle-Ion Interactions in Aerosol Reactors by Girish Sharma A dissertation presented to The Graduate School of Washington University in partial fulfillment of the requirements for the degree of Doctor of Philosophy May 2020 Saint Louis, Missouri © 2020, Girish Sharma Table of Contents List of Figures .............................................................................................................................. vii List of Tables ............................................................................................................................. xvii Acknowledgements .................................................................................................................. xviii Abstract of the Dissertation ..................................................................................................... xxii Chapter 1. Introduction ............................................................................................................... 1 1.1 Background and Motivation ......................................................................................... 2 1.1.1 Synthesis of ‘good’ aerosols ................................................................................... 2 1.1.2 Measurement of 1-10 nm sized particles ............................................................... 4 1.1.3 Capture of ‘bad’ aerosols ....................................................................................... 8 1.2 Dissertation Outline ....................................................................................................... 9 1.3 References ..................................................................................................................... 10 Chapter 2. Collisional Growth Rate and Correction Factor for TiO2 Nanoparticles at High Temperatures in Free Molecular Regime ................................................................................. 17 Abstract ................................................................................................................................ 18 2.1 Introduction .................................................................................................................. 19 2.2 Methods ......................................................................................................................... 23 2.2.1 Experimental Set up ............................................................................................. 23 2.2.2 Analysis ........................................................................................................................ 27 2.3 Results and Discussion ................................................................................................. 31 2.3.1 Dilution Ratio .............................................................................................................. 31 2.3.2 Lognormal PSD of spherical TiO2 nanoparticles .................................................... 32 2.3.3 Collisional correction factor ( ) at different temperatures ................................... 34 2.4 Conclusions ................................................................................................................... 40 2.5 References ..................................................................................................................... 41 Chapter 3. Molecular dynamics trajectory calculations for collisional growth rates of titania nanoparticles during gas-phase synthesis at high temperatures ................................ 48 Abstract .................................................................................................................................... 49 3.1 Introduction .................................................................................................................. 50 3.2 Methodology ................................................................................................................. 54 ii 3.2.1 MD Trajectory Calculations ................................................................................ 54 3.2.2 Nanoparticle Equilibration and Collisions ......................................................... 57 3.3 Results and Discussions ............................................................................................... 58 3.3.1 Dipole Moment of Equilibrated Titania Nanoparticles ..................................... 58 3.3.2 Collisions of equally sized particles ..................................................................... 60 3.3.3 Collisions of unequally sized particles ................................................................ 63 3.3.4 Comparison with experiments and models ........................................................ 65 3.4 Conclusions ................................................................................................................... 67 3.5 References ..................................................................................................................... 68 Chapter 4. Role played by charge in early stages (1-10 nm) of TiO2 particle formation and growth in premixed flames ......................................................................................................... 73 Abstract ................................................................................................................................ 74 4.1 Introduction .................................................................................................................. 75 4.2 Methods ......................................................................................................................... 78 4.2.1 Experimental Set-up ............................................................................................. 78 4.2.2 Data inversion from Half-mini DMA .................................................................. 80 4.2.3 Experimental Plan ................................................................................................ 82 4.3 Results and Discussions ............................................................................................... 83 4.3.1 Blank Flame Ions (Ar v/s N2) ............................................................................... 83 4.3.2 Effect of diluent on particle charging (N2 v/s Ar) .............................................. 85 4.3.3 Effect of sampling height on particle charging .................................................. 87 4.3.4 Effect of precursor concentration on particle charging .................................... 91 4.4 Conclusions ................................................................................................................... 94 4.5 References ..................................................................................................................... 95 Chapter 5. Modeling Simultaneous Coagulation and Charging of Nanoparticles at High Temperatures Using the Method of Moments........................................................................ 101 Abstract .................................................................................................................................. 102 5.1 Introduction ................................................................................................................ 105 5.2 Model description ....................................................................................................... 107 5.2.1 Ion attachment coefficient .................................................................................. 107 5.2.2 Coagulation Coefficient ...................................................................................... 110 5.2.3 Solving for simultaneous coagulation and charging using MoM ................... 112 5.2.4 Charging terms of the GDE ............................................................................... 115 iii 5.2.5 Coagulation terms of the GDE........................................................................... 116 5.2.6 Ion Balance .......................................................................................................... 119 5.3 Simulation Results and Comparison with the MdM .............................................. 119 5.3.1