Experiments and Numerical Simulations of Diluted Spray Turbulent Combustion: Proceedings of the 1st International Workshop on Turbulent Spray Combustion (ERCOFTAC Series, 17)

This book reflects the outcome of the 1st International Workshop on Turbulent Spray Combustion held in 2009 in Corsica (France). The focus is on reporting the progress of experimental and numerical techniques in two-phase flows, with emphasis on spray combustion.¡ The motivation for studies in this area is that knowledge of the dominant phenomena and their interactions in such flow systems is essential for the development of predictive models and their use in combustor and gas turbine design. This necessitates the development of accurate experimental methods and numerical modelling techniques.¡ The workshop aimed at providing an opportunity for experts and young researchers to present the state-of-the-art, discuss new developments or techniques and exchange ideas in the areas of experimentations, modelling and simulation of reactive multiphase flows. The first two papers reflect the contents of the invited lectures, given by experts in the field of turbulent spray combustion. The first ¡concerns computational issues, while the second deals with experiments. These lectures initiated very interesting and interactive discussions among the researchers, further pursued in contributed poster presentations. Contributions 3 and 4 focus on some aspects of the impact of the interaction between fuel evaporation and combustion on spray combustion in the context of gas turbines, while the final article deals with the interaction between evaporation and turbulence Cover 1 ERCOFTAC Series 17 3 Experiments and Numerical Simulations of Diluted Spray Turbulent Combustion 4 ISBN 9789400714083 5 Preface 6 Contents 8 Chapter 1: Issues in Computational Studies of Turbulent Spray Combustion 12 1 Introduction 13 2 Spray Atomization 14 3 Droplet Evaporation and Combustion 19 4 Spray Combustion 25 4.1 Euler-Euler Models 25 4.2 Euler-Lagrange Models 27 4.3 Turbulence Modeling 31 4.4 Chemical Reactions in Spray Flows 38 5 Summary and Conclusions 46 References 46 Chapter 2: Details and Complexities of Boundary Conditions in Turbulent Piloted Dilute Spray Jets and Flames 52 1 Introduction 52 2 Experimental 55 2.1 The Burner 55 2.2 The Measurement Techniques 57 2.3 The Blow-Off Limits 58 2.4 The Selected Cases 59 3 The Boundary Conditions 63 3.1 Droplet Velocity Profiles 63 3.2 Droplet Size Distribution 66 4 Comparison with Gaseous Jets 70 5 The Spray-Pipe Anomaly 73 6 Concluding Remarks 76 References 77 Chapter 3: Toward the Impact of Fuel Evaporation-Combustion Interaction on Spray Combustion in Gas Turbine Combustion Chambers. Part I: Effect of Partial Fuel Vaporization on Spray Combustion 80 1 Introduction 82 2 Mathematical Models and Numerical Procedures 86 2.1 Governing Equations for Turbulent Gaseous Flow 86 2.2 Two-Way Coupling and Turbulence Modulation 87 2.3 Droplet Description, Dispersion and Evaporation 88 2.3.1 Droplet Description 88 2.3.2 Turbulent Droplet Dispersion 89 2.3.3 Evaporation 90 2.4 Combustion Modeling 93 2.5 Numerical Procedure and Coupling 96 3 Configurations 97 3.1 Geometry Description 97 3.2 Numerical Set Up and Boundary Conditions 99 4 Results and Discussion 99 4.1 Influence of Mixing Air Temperature and Pre-vaporization Tube Length on Vaporization Degree (Case A) 101 4.2 Influence of Evaporation Models (Case C) 105 4.3 Influence of Vaporization Zone Length (Case B) 109 4.4 Influence of Droplet Diameter (Case D) 110 4.5 Influence of Flammability Limit (Case E) 111 4.6 Influence of Ignition Location (Case F) 112 4.7 Influence of Model Parameters 114 4.7.1 The Fractal Dimension D (Case G) 114 4.7.2 The Modeling of the Evaporation Source Term in the Mixture Fraction Variance Equation (Case H) 115 4.7.3 The Parameter CZ in the Production/Sink Term (Case I) 118 5 Concluding Remarks 118 References 119 Chapter 4: Toward the Impact of Fuel Evaporation-Combustion Interaction on Spray Combustion in Gas Turbine Combustion Chambers. Part II: Influence of High Combustion Temperature on Spray Droplet Evaporation 122 1 Introduction 123 2 Outline of Combustion Modelling for N-heptane Fuel and Numerical Procedures 125 3 Configurations and Boundary Conditions 126 3.1 Geometry 126 3.2 Numerical Setup and Boundary Conditions 127 4 Results and Discussion 129 4.1 Carrier Gas Properties in Non-Reacting Case 129 4.2 Turbulent Droplet Dispersion in Non-reacting Case 132 4.3 Spray Evaporation in Non-reacting Case 134 4.4 Turbulent Droplet Dispersion in Reacting Case 136 4.5 Spray Evaporation in Reacting Case 140 5 Conclusions 141 References 142 Chapter 5: Reynolds Stress and PDF Modeling of Two-Way Coupling and Vaporisation Interaction in a Turbulent Spray Flame 144 1 Introduction 145 2 Theoretical Framework 146 2.1 Pressure-Rate-of-Strain Model 148 2.2 Lagrangian Monte Carlo Method 150 2.3 Modeling of Fluctuating Acceleration 150 2.4 Modification of the Diffusion Term in Dispersed Two Phase Flows 152 2.5 Consistency with Second Moment Closures 154 2.5.1 Single Phase Flow 155 2.5.2 Contribution of the Fluid-Particle Interaction 156 2.5.3 Contribution of Mass Transfer 156 2.6 Evolution Equation for Gas Phase Particles 157 2.7 Governing Equations for the Dispersed Phase 160 2.7.1 Acceleration Model 160 2.7.2 Evaporation Model 161 2.7.3 Drag and Heat Transfer Modification Due to Vaporisation 162 3 Spray Flame Simulations 163 3.1 Dispersed Phase 164 4 Results and Discussion 165 4.1 Gas Phase Results 165 4.2 Dispersed Phase Results 169 5 Conclusions 171 References 174 Index 178 9400714084,9789400714083 Springer 2011 Front Matter....Pages i-x Issues in Computational Studies of Turbulent Spray Combustion....Pages 1-39 Details and Complexities of Boundary Conditions in Turbulent Piloted Dilute Spray Jets and Flames....Pages 41-68 Toward the Impact of Fuel Evaporation-Combustion Interaction on Spray Combustion in Gas Turbine Combustion Chambers. Part I: Effect of Partial Fuel Vaporization on Spray Combustion....Pages 69-110 Toward the Impact of Fuel Evaporation-Combustion Interaction on Spray Combustion in Gas Turbine Combustion Chambers. Part II: Influence of High Combustion Temperature on Spray Droplet Evaporation....Pages 111-132 Reynolds Stress and PDF Modeling of Two-Way Coupling and Vaporisation Interaction in a Turbulent Spray Flame....Pages 133-165 Back Matter....Pages 167-171