Book contents
- Frontmatter
- Contents
- Preface
- INTRODUCTION
- 1 CHEMICAL THERMODYNAMICS
- 2 CHEMICAL KINETICS
- 3 OXIDATION MECHANISMS OF FUELS
- 4 TRANSPORT PHENOMENA
- 5 CONSERVATION EQUATIONS
- 6 LAMINAR NONPREMIXED FLAMES
- 7 LAMINAR PREMIXED FLAMES
- 8 LIMIT PHENOMENA
- 9 ASYMPTOTIC STRUCTURE OF FLAMES
- 10 AERODYNAMICS OF LAMINAR FLAMES
- 11 COMBUSTION IN TURBULENT FLOWS
- 12 COMBUSTION IN BOUNDARY-LAYER FLOWS
- 13 COMBUSTION IN TWO-PHASE FLOWS
- 14 COMBUSTION IN SUPERSONIC FLOWS
- References
- Author Index
- Subject Index
11 - COMBUSTION IN TURBULENT FLOWS
Published online by Cambridge University Press: 06 July 2010
- Frontmatter
- Contents
- Preface
- INTRODUCTION
- 1 CHEMICAL THERMODYNAMICS
- 2 CHEMICAL KINETICS
- 3 OXIDATION MECHANISMS OF FUELS
- 4 TRANSPORT PHENOMENA
- 5 CONSERVATION EQUATIONS
- 6 LAMINAR NONPREMIXED FLAMES
- 7 LAMINAR PREMIXED FLAMES
- 8 LIMIT PHENOMENA
- 9 ASYMPTOTIC STRUCTURE OF FLAMES
- 10 AERODYNAMICS OF LAMINAR FLAMES
- 11 COMBUSTION IN TURBULENT FLOWS
- 12 COMBUSTION IN BOUNDARY-LAYER FLOWS
- 13 COMBUSTION IN TWO-PHASE FLOWS
- 14 COMBUSTION IN SUPERSONIC FLOWS
- References
- Author Index
- Subject Index
Summary
GENERAL CONCEPTS
Most flows in practical combustion devices are turbulent, characterized by the presence of rapid, random fluctuations of the flow velocity and scalar properties at a given point in space. These fluctuations spread out in a manner similar to molecular diffusion as the flow evolves in time and/or proceeds downstream. Figure 11.1.1 illustrates various canonical flow configurations that are often encountered in practical combustion systems: unconfined flows such as jets and mixing layers, semiconfined flows over solid surfaces, confined flows in ducts, reverse flows in wakes, and buoyant flows.
Turbulence remains one of the most challenging and unsolved problems in physics. The complexity further increases when chemical reactions are also present. Because of these difficulties, studies on turbulent combustion have been mostly empirical until the late 1970s. Advances since then have identified fruitful paths for rational investigation. In this chapter we present a brief account of the current state of understanding.
In the next two sections the general concepts and solution techniques of turbulent flows, mostly nonreacting, are presented. These are followed by separate discussions on turbulent premixed and nonpremixed combustion. For a more detailed exposition, the reader is referred to Monin and Yaglom (1965), Tennekes and Lumley (1972), Launder and Spalding (1972), Hinze (1975), Schlichting et al. (1999), and Pope (2000) for nonreacting turbulent flows, and to Libby and Williams (1980, 1994), Williams (1985), Peters (2000), and Poinsot and Veynante (2005) for reacting turbulent flows.
- Type
- Chapter
- Information
- Combustion Physics , pp. 474 - 515Publisher: Cambridge University PressPrint publication year: 2006