Chapter 1 Introduction 001 1．1 Background 002 1．2 Motivation 004 1．3 Outline 007 Chapter 2 Study of the filtration performance of multi-fiber filters 009 2．1 Introduction 011 2．2 Model of multi-fiber filters 014 2．2．1 Geometric model and simulation method of multi-fiber filters 014 2．2．2 Model validation 016 2．3 Filtration efficiency and its optimization 020 2．3．1 Comparison of filtration performance between parallel and staggered designs 020 2．3．2 Filtration efficiency at different face velocities and particle diameters 022 2．3．3 Filtration performance of layered filters with the same total SVF 024 2．3．4 Optimization of pressure drop and filtration efficiency 025 2．4 Conclusion 028 References 030 Chapter 3 Study of particle rebound and deposition on fiber surface 034 3．1 Introduction 036 3．2 Models of flow field and particle movement 041 3．2．1 Flow field and particle movement 041 3．2．2 Particle rebound model 044 ? 3．3 Particle transport and deposition 048 3．3．1 Effect of particle rebounds on particle deposition 048 3．3．2 Effects of face velocity on particle deposition 050 3．3．3 Effects of particle diameter on particle deposition 052 3．3．4 Filtration efficiency of a single fiber 054 3．4 Conclusion 057 References 059 Chapter 4 Investigation of the flow-field in the upper respiratory system when wearing N95 FFR 064 4．1 Introduction 066 4．2 Modeling of full breathing cycles 068 4．2．1 Flow field reverse modeling 068 4．2．2 CFD simulation of a full breathing cycle 071 4．3 Flow field of a full breathing cycle 074 4．3．1 Flow characteristics of a full breathing cycle 074 4．3．2 CO2 volume fraction 075 4．3．3 Temperature distribution inside FFR cavity 077 4．3．4 Pressure and wall shear stress inside upper respiratory airway 079 4．4 Discussion 082 4．5 Conclusion 085 References 086 Chapter 5 Investigation of water vapor condensation on the inner surface of N95 FFR 089 5．1 Introduction 091 5．2 CFD modeling of water vapor condensation 093 5．2．1 Model of water vapor condensation 093 5．2．2 CFD-setup and boundary conditions of water vapor condensation 093 5．3 Water vapor condensation on the inner surface of N95 FFR 097 5．3．1 Effects of different environmental temperatures 099 5．3．2 Effects of different breathing velocities 102 5．3．3 Effects of different breathing frequencies 104 5．4 Discussion 108 5．5 Conclusion 110 References 111 Chapter 6 Effect of vapor condensation on micro-climate in the deadspace of N95 FFR 113 6．1 Introduction 115 6．2 CFD modeling of vapor condensation 117 6．2．1 Model of vapor condensation 117 6．2．2 CFD-setup and boundary conditions of vapor condensation 118 6．2．3 FFR performance and vapor condensation distribution 120 6．3 Experiment of micro-climate inside N95 FFR 126 6．3．1 Experiment of temperature and relative humidity measuring inside FFR 127 6．3．2 Experiment of bacteria accounting on the inner surface of FFR 129 6．4 Conclusion 133 References 134 Chapter 7 Investigation of movement characteristics and respiratory deposition of indoor cigarette particles 136 7．1 Introduction 138 7．2 Model of particle movement and respiratory deposition 141 7．2．1 Description of room， human and particles system 141 7．2．2 CFD model of cigarette particles deposition 143 7．2．3 PM2．5 measurement 146 7．3 Flow field and cigarette particles deposition 147 7．4 Conclusion 155 References 156 Chapter 8 An improved FFR design with a ventilation fan： CFD simulation and validation 159 8．1 Introduction 161 8．2 Improved FFR design and CFD simulation 163 8．2．1 Improved FFR design 163 8．2．2 Simulation method of flow field in FFR 164 8．3 Performance of the ventilation fan and its effects 169 8．3．1 Flow characteristics of the ventilation fan 169 8．3．2 Effects of fan orientation 170 8．3．3 Experiment on temperature of headform and FFR 172 8．4 Conclusion 177 References 178 Chapter 9 Design of the FFR with an intelligent control fan 181 9．1 Introduction 183 9．2 Improved FFR design 184 9．3 Design of intelligent control system 186 9．4 Test results of FFR performance 189 9．5 Discussion 193 9．6 Conclusion 194 References 195 Chapter 10 Study of contact characteristics between a respirator and a headform 196 10．1 Introduction 198 10．2 Models and methods of contact characteristics between a respirator and a headform 202 10．2．1 Geometric models of headform and respirator 202 10．2．2 Simulation methods of contact characteristics 205 10．3 Contact characteristics between a respirator and a headform 208 10．4 Conclusion 214 References 216 Chapter 11 The effects of facial expressions on respirators fit 218 11．1 Introduction 220 11．2 Models and methods of facial expressions 223 11．2．1 FE models of the headfrom and respirator 223 11．2．2 Simulation methods of facial expressions 225 11．3 Effects of facial expressions on respirators fit 227 11．4 Conclusion 234 References 236 Chapter 12 Customized design and 3D printing of face seal for an N95 FFR 238 12．1 Introduction 240 12．2 Design， manufacture and test of customized face seals 242 12．2．1 3D laser scanning of human headform 243 12．2．2 Customized design of FFR face seal 243 12．2．3 3D printing of the FFR face seal 245 12．2．4 Experiment setup and procedures 245 12．3 Contact characteristics between the FFR and headform 249 12．4 Discussion 253 12．5 Conclusion 255 References 256
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