Charge Injection Systems (eBook)

Nomenclature 5
Contents 7
Chapter 1 Introduction 11
Introduction and Scope 11
Organization 13
Chapter 2 Electrostatics, Electrohydrodynamic Flow, Coupling and Instability 15
Electrostatics 15
{/it The Coulomb Force} 15
{/it Permittivity} 16
{/it Conductors, Insulators, Dielectrics and Polarization} 16
{/it Gauss’s Law} 18
Mobility and Charge Transport 20
{/it Introduction} 20
{/it Convective Transport by Fluid Motion} 20
{/it Mobility and the Drift Term} 20
{/it Diffusion and the Debye Length} 21
{/it Charge Conservation} 22
Momentum and Energy 23
{/it Introduction} 23
{/it Electrical Forces} 23
{/it Momentum Conservation} 24
{/it Energy Conservation} 24
Electrical Timescales 25
{/it Introduction} 25
{/it Ohmic-Charge Relaxation} 25
{/it Space-Charge Relaxation} 25
{/it Ionic Diffusion Timescale} 26
{/it Ionic Transit Timescale} 26
{/it Electro-viscous Timescale} 27
{/it Electro-inertial Timescale} 27
Non-dimensional Transport Equations 27
{/it Introduction} 27
{/it Momentum Conservation: Free Flow} 28
{/it Momentum Conservation: Forced Flow} 29
{/it Non-dimensional Parameters} 29
Electrohydrodynamics 31
{/it Introduction} 31
{/it Fundamentals} 32
{/it Instability} 32
{/it Plumes} 36
{/it Transition to Turbulence} 39
Electrohydrodynamic Turbulence in a Propagating Flow Front 40
{/it EHD Vorticity} 40
{/it EHD RANS in a Propagating Flow Front} 41
{/it Transient Turbulence} 42
{/it AC Turbulence} 43
{/it Current and Voltage} 43
Chapter Summary 45
Chapter 3 Charge Injection into a Quiescent Dielectric Liquid 46
Charge and Field Distribution 46
{/it Field Emission and Ionization} 46
{/it Electrochemical} 47
{/it Ohmic Conduction} 48
{/it Space-Charge} 48
{/it Point Sharpness} 48
{/it Hyperbolic Field Expression} 49
IV Characteristics of Point-Plane Systems 49
{/it Steady-State Behavior} 49
{/it Current Instabilities} 53
Vapor Bubble Creation and Pressure Dependence in Liquids 58
{/it Vapor Bubble Formation} 58
{/it Vapor Bubble Growth: Pulsed Voltage Operation} 60
{/it Vapor Bubble Growth: Constant Voltage} 61
{/it Vapor Bubble Evolution} 67
Chapter Summary 69
Chapter 4 Single Charged Drop Stability, Evaporation and Combustion 70
Maximum Spherical Drop Charge 70
Maximum Spheroidal Drop Charge 78
Spheroidal Deformation of Non-stationary Charged Drops 79
Models for Products of Charged Drop Disruption 81
Combustion of Single Drops 85
Summary 86
Chapter 5 Charge Injection Atomizers: Design and Electrical Performance 87
Overview: Electrostatic Atomization for Electrically Semi-conducting Liquids 87
Overview: Electrostatic Atomization for Electrically Insulating Liquids 89
Atomizer Construction 90
Nozzle Design 92
Rig Design 93
Liquids Used 94
Breakdown Limits and Typical Current-Voltage Response 95
{/it Sub-critical Breakdown} 95
{/it Super-critical Breakdown} 99
{/it Overview of the Breakdown Regimes} 102
Total Current Versus Voltage: Observations 102
Total Current Versus Voltage: Comparison to Quiescent Fluid Data 104
Effect of Flow-Rate/Injection Velocity 108
Specific Charge Regimes 109
Specific Charge: Summary 114
Variation of Electrode Gap Ratio (L_{i}/d), L_{0}/d=2, d=500$/mu$m, Version 1 Design 115
Variation of d: Version 1 Design: Constant Q, L_{i}, L_{0}/d 118
Variation of Electrode Gap Ratio (L_{i}/d): Version 2 Design, d=500$/mu$m 120
Variation of Electrode Gap Ratio (L_{i}/d): Version 2 Design, d=250$/mu$m 122
Performance Evaluation: Version 1 and Version 2 124
Point-Plane Atomizer Design Modifications 125
Beyond the Point-Plane Atomizer Concept 129
{/it Single Hole Electrostatically Enhanced Pressure Swirl Atomizers} 129
{/it Multi-hole Charge Injection Atomizers} 130
{/it Pulsed Spray Charge Injection Atomizers} 130
{/it Other Developments within Charge Injection Atomization} 131
Chapter Summary 131
Chapter 6 Jet Instability and Primary Atomization 133
Measured Characteristics 133
Orifice Channel Space Charge Distribution Model 140
Chapter Summary 145
Chapter 7 Spray Characterization and Combustion 146
Spray Visualization and Prediction of Expansion Rate 146
Quantitative Spray Characteristics 153
Estimation of the Radial Profile of Spray Specific Charge 161
Models for Drop Diameter and Charge Distributions 167
{/it Energy Minimization Methods} 167
{/it Spray Theory of Kelly} 170
Spray Combustion 180
Summary 185
Chapter 8 Conclusions and Future Outlook 187
Conclusions 187
Future Outlook 189
References 191
Index 201