AN INTRODUCTION TO COMBUSTION CONCEPTS AND APPLICATIONSPDF电子书下载

1 Introduction 1

Motivation to Study Combustion 1

A Definition of Combustion 6

Combustion Modes and Flame Types 6

Approach to Our Study 8

References 8

2 Combustion and Thermochemistry 9

Overview 9

Review of Property Relations 9

Extensive and Intensive Properties 9

Equation of State 10

Calorific Equations of State 11

Ideal-Gas Mixtures 13

Latent Heat of Vaporization 15

First Law of Thermodynamics 16

First Law—Fixed Mass 16

First Law—Control Volume 17

Reactant and Product Mixtures 18

Stoichiometry 18

Absolute（or Standardized）Enthalpy and Enthalpy of Formation 24

Enthalpy of Combustion and Heating Values 27

Adiabatic Flame Temperatures 32

Chemical Equilibrium 36

Second-Law Considerations 36

Gibbs Function 38

Complex Systems 44

Equilibrium Products of Combustion 45

Full Equilibrium 45

Water-Gas Equilibrium 47

Pressure Effects 51

Some Applications 52

Recuperation and Regeneration 52

Flue-（or Exhaust-）Gas Recirculation 58

Summary 66

Nomenclature 66

References 68

Review Questions 69

Problems 70

Appendix 2A—Some Fuel Chemistry 78

3 Introduction to Mass Transfer 83

Overview 83

Rudiments of Mass Transfer 83

Mass Transfer Rate Laws 84

Species Conservation 90

Some Applications of Mass Transfer 92

The Stefan Problem 92

Liquid-Vapor Interface Boundary Conditions 94

Droplet Evaporation 98

Summary 105

Nomenclature 105

References 107

Review Questions 107

Problems 108

4 Chemical Kinetics 111

Overview 111

Global versus Elementary Reactions 112

Elementary Reaction Rates 113

Bimolecular Reactions and Collision Theory 113

Other Elementary Reactions 118

Rates of Reaction for Multistep Mechanisms 119

Net Production Rates 119

Compact Notation 121

Relation between Rate Coefficients and Equilibrium Constants 122

Steady-State Approximation 125

The Mechanism for Unimolecular Reactions 126

Chain and Chain-Branching Reactions 127

Chemical Time Scales 133

Partial Equilibrium 138

Summary 140

Nomenclature 140

References 141

Questions and Problems 143

5 Some Important Chemical Mechanisms 148

Overview 148

The H2-O2 System 148

Carbon Monoxide Oxidation 152

Oxidation of Higher Paraffins 153

General Scheme 153

Global and Quasi-global Mechanism 156

Methane Combustion 158

Complex Mechanism 158

High-Temperature Reaction Pathway Analysis 158

Low-Temperature Reaction Pathway Analysis 166

Oxides of Nitrogen Formation 168

Summary 171

References 172

Questions and Problems 174

6 Coupling Chemical and Thermal Analyses of Reacting Systems 178

Overview 178

Constant-Pressure， Fixed-Mass Reactor 179

Application of Conservation Laws 179

Reactor Model Summary 182

Constant-Volume，Fixed-Mass Reactor 182

Application of Conservation Laws 182

Reactor Model Summary 183

Well-Stirred Reactor 189

Application of Conservation Laws 190

Reactor Model Summary 192

Plug-Flow Reactor 200

Assumptions 200

Application of Conservation Laws 201

Applications to Combustion System Modeling 205

Summary 206

Nomenclature 206

References 208

Problems and Projects 209

Appendix 6A—Some Useful Relationships among Mass Fractions，Mole Fractions，Molar Concentrations，and Mixture Molecular Weights 214

7 Simplified Conservation Equations for Reacting Flows 215

Overview 215

Overall Mass Conservation（Continuity） 216

Species Mass Conservation（Species Continuity） 218

Multicomponent Diffusion 221

General Formulations 222

Calculation of Multicomponent Diffusion Coefficients 223

Simplified Approach 226

Momentum Conservation 229

One-Dimensional Forms 229

Two-Dimensional Forms 230

Energy Conservation 234

General One-Dimensional Form 234

Shvab-Zeldovich Forms 236

Useful Form for Flame Calculations 240

The Concept of a Conserved Scalar 241

Definition of Mixture Fraction 241

Conservation of Mixture Fraction 242

Conserved Scalar Energy Equation 246

Summary 247

Nomenclature 248

References 249

Review Questions 250

Problems 251

8 Laminar Premixed Flames 253

Overview 253

Physical Description 254

Definition 254

Principal Characteristics 254

Typical Laboratory Flames 256

Simplified Analysis 261

Assumptions 262

Conservation Laws 262

Solution 264

Detailed Analysis 269

Governing Equations 269

Boundary Conditions 270

Structure of CH4-Air Flame 271

Factors Influencing Flame Velocity and Thickness 274

Temperature 274

Pressure 277

Equivalence Ratio 278

Fuel Type 278

Flame Speed Correlations for Selected Fuels 278

Quenching，Flammability，and Ignition 283

Quenching by a Cold Wall 284

Flammability Limits 289

Ignition 291

Flame Stabilization 294

Summary 298

Nomenclature 299

References 300

Review Questions 302

Problems 302

9 Laminar Diffusion Flames 305

Overview 305

Nonreacting Constant-Density Laminar Jet 306

Physical Description 306

Assumptions 307

Conservation Laws 308

Boundary Conditions 308

Solution 309

Jet Flame Physical Description 314

Simplified Theoretical Descriptions 317

Primary Assumptions 318

Basic Conservation Equations 318

Additional Relations 319

Conserved Scalar Approach 320

Various Solutions 327

Flame Lengths for Circular-Port and Slot Burners 331

Roper’s Correlations 331

Flowrate and Geometry Effects 336

Factors Affecting Stoichiometry 336

Soot Formation and Destruction 343

Counterflow Flames 347

Mathematical Description 348

Structure of CH4-Air Flame 350

Summary 354

Nomenclature 354

References 356

Review Questions 359

Problems 359

10 Droplet Evaporation and Burning 362

Overview 362

Some Applications 362

Diesel Engines 363

Gas-Turbine Engines 365

Liquid-Rocket Engines 367

Simple Model of Droplet Evaporation 367

Assumptions 370

Gas-Phase Analysis 372

Droplet Lifetimes 375

Simple Model of Droplet Burning 378

Assumptions 379

Problem Statement 380

Mass Conservation 381

Species Conservation 381

Energy Conservation 383

Summary and Solution 389

Burning Rate Constant and Droplet Lifetimes 391

Extension to Convective Environments 395

Additional Factors 398

One-Dimensional Vaporization-Controlled Combustion 399

Physical Model 399

Assumptions 401

Mathematical Problem Statement 401

Analysis 402

Model Summary 410

Summary 410

Nomenclature 413

References 415

Problems 418

Projects 420

Appendix 10A—Sir Harry R. Ricardo’s Description of Combustion in Diesel Engines 421

11 Introduction to Turbulent Flows 423

Overview 423

Definition of Turbulence 424

Length Scales in Turbulent Flows 427

Four Length Scales 427

Turbulence Reynolds Numbers 430

Analyzing Turbulent Flows 434

Reynolds Averaging and Turbulent Stresses 435

The Closure Problem 437

Axisymmetric Turbulent Jet 441

Beyond the Simplest Model 444

Summary 445

Nomenclature 446

References 447

Questions and Problems 449

12 Turbulent Premixed Flames 450

Overview 450

Some Applications 450

Spark-Ignition Engines 450

Gas-Turbine Engines 451

Industrial Gas Burners 452

Definition of Turbulent Flame Speed 454

Structure of Turbulent Premixed Flames 456

Experimental Observations 456

Three Flame Regimes 457

Wrinkled Laminar-Flame Regime 462

Distributed-Reaction Regime 466

Flamelets-in-Eddies Regime 468

Flame Stabilization 470

Bypass Ports 470

Burner Tiles 471

Bluff Bodies 471

Swirl or Jet-Induced Recirculating Flows 473

Summary 474

Nomenclature 475

References 476

Problems 478

13 Turbulent Nonpremixed Flames 481

Overview 481

Jet Flames 484

General Observations 484

Simplified Analysis 489

Flame Length 495

Flame Radiation 501

Liftoff and Blowout 504

Other Configurations 509

Summary 512

Nomenclature 513

References 514

Review Questions 517

Problems 517

14 Burning of Solids 519

Overview 519

Coal-Fired Boilers 520

Heterogeneous Reactions 520

Burning of Carbon 522

Overview 523

One-Film Model 524

Two-Film Model 536

Particle Burning Times 542

Coal Combustion 544

Other Solids 545

Summary 545

Nomenclature 546

References 547

Questions and Problems 548

15 Pollutant Emissions 550

Overview 550

Effects of Pollutants 551

Quantification of Emissions 553

Emission Indices 553

Corrected Concentrations 555

Various Specific Emission Measures 558

Emissions from Premixed Combustion 559

Oxides of Nitrogen 559

Carbon Monoxide 567

Unburned Hydrocarbons 568

Catalytic Aftertreatment 569

Particulate Matter 571

Emissions from Nonpremixed Combustion 572

Oxides of Nitrogen 573

Unburned Hydrocarbons and Carbon Monoxide 584

Particulate Matter 586

Oxides of Sulfur 586

Summary 587

Nomenclature 588

References 589

Questions and Problems 594

16 Detonations 598

Overview 598

Physical Description 598

Definition 598

Principal Characteristics 599

One-Dimensional Analysis 600

Assumptions 600

Conservation Laws 601

Combined Relations 602

Detonation Velocities 609

Structure of Detonation Waves 613

Summary 617

Nomenclature 618

References 619

Problems 620

Appendix A Selected Thermodynamic Properties of Gases Comprising C—H—O—N System 621

Appendix B Fuel Properties 648

Appendix c Selected Properties of Air，Nitrogen，and Oxygen 653

Appendix D Binary Diffusion Coefficients and Methodology for their Estimation 656

Appendix E Generalized Newton’s Method for the Solution of Nonlinear Equations 659

Appendix F Computer Codes for Equilibrium Products of Hydrocarbon—Air Combustion 662

Index 665