Book contents
- Frontmatter
- Contents
- Preface
- Nomenclature
- 1 Introduction
- 2 Isolated Spherically Symmetric Droplet Vaporization and Heating
- 3 Convective Droplet Vaporization, Heating, and Acceleration
- 4 Multicomponent-Liquid Droplets
- 5 Droplet Behavior under Near-Critical, Transcritical, and Supercritical Conditions
- 6 Droplet Arrays and Groups
- 7 Spray Equations
- 8 Computational Issues
- 9 Spray Applications
- 10 Spray Interactions with Turbulence and Vortical Structures
- 11 Film Vaporization
- 12 Stability of Liquid Streams
- Appendix A The Field Equations
- Appendix B Conserved Scalars
- Appendix C Droplet-Model Summary
- Bibliography
- Index
6 - Droplet Arrays and Groups
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface
- Nomenclature
- 1 Introduction
- 2 Isolated Spherically Symmetric Droplet Vaporization and Heating
- 3 Convective Droplet Vaporization, Heating, and Acceleration
- 4 Multicomponent-Liquid Droplets
- 5 Droplet Behavior under Near-Critical, Transcritical, and Supercritical Conditions
- 6 Droplet Arrays and Groups
- 7 Spray Equations
- 8 Computational Issues
- 9 Spray Applications
- 10 Spray Interactions with Turbulence and Vortical Structures
- 11 Film Vaporization
- 12 Stability of Liquid Streams
- Appendix A The Field Equations
- Appendix B Conserved Scalars
- Appendix C Droplet-Model Summary
- Bibliography
- Index
Summary
To this point in this book, we have discussed only isolated droplets. In a practical situation, of course, many droplets are present in a spray, and the average distance between droplets can become as low as a few droplet diameters. A typical droplet therefore will not behave as an isolated droplet; rather, it will be strongly influenced by immediately neighboring droplets and, to some extent, by all droplets in the spray.
There are three levels of interaction among neighboring droplets in a spray. If droplets are sufficiently far apart, the only impact is that neighboring droplets (through their exchanges of mass, momentum, and energy with the surrounding gas) will affect the ambient conditions of the gas field surrounding a given droplet. As the distance between droplets becomes larger, the influence of neighboring droplets becomes smaller and tends toward zero ultimately. At this first level of interaction, the geometrical configuration of the (mass, momentum, and energy) exchanges between a droplet and its surrounding gas is not affected by the neighboring droplets. In particular, the Nusselt number, Sherwood number, and lift and drag coefficients are identical in values to those for an isolated droplet. This type of interaction will be fully discussed in Chapter 9.
At the next level of interaction, droplets are closer to each other, on average, and the geometrical configurations of the exchanges with the surrounding gas are modified.
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- Fluid Dynamics and Transport of Droplets and Sprays , pp. 150 - 198Publisher: Cambridge University PressPrint publication year: 2010