Turbulent Particle-Laden Gas Flows

Turbulent Particle-Laden Gas Flows

-

English

Description

Results are given of experimental and theoretical studies of "gas-solid particles" turbulent two-phase flows. Special emphasis is placed on studies of the behavior of particles suspended in a turbulent gas flow and their feedback effect on the characteristics of flow of the carrier phase. The characteristics of heterogeneous flows in channels (pipes) are analyzed, as well as those in the vicinity of the critical points of bodies subjected to flow and in the boundary layer developing on their surface. Problems of physical simulation of turbulent gas flows which carry solid particles are treated in detail. This monograph will be useful for researchers involved in investigations of gas dynamics and heat and mass transfer in multiphase flows, as well as for university professors, post-graduate students, and students.

Subjects

Informations

Published by
Published 05 July 2007
Reads 1
EAN13 9783540680543
License: All rights reserved
Language English
Report a problem
Contents
1
2
Concise Information About SinglePhase and Heterogeneous Turbulent Flows. . . . . . . . . . . . . . . . . . . . 1.1 Preliminary Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Equations of Single-Phase Turbulent Flows . . . . . . . . . . . . . . . 1.2.1 Algebraic Models of Turbulence . . . . . . . . . . . . . . . . . . 1.2.2 One-Parameter Models of Turbulence . . . . . . . . . . . . . . 1.2.3 Two-Parameter Models of Turbulence . . . . . . . . . . . . . 1.3 Main Characteristics of Single-Phase Flows . . . . . . . . . . . . . . 1.3.1 Distributions of Averaged Velocity . . . . . . . . . . . . . . . . 1.3.2 Distributions of Averaged Fluctuation Velocities . . . . 1.3.3 Turbulent Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3.4 Energy Spectrum of Turbulence . . . . . . . . . . . . . . . . . . 1.3.5 Correlations in Turbulent Flows . . . . . . . . . . . . . . . . . . 1.3.6 Scales of Turbulent Flows . . . . . . . . . . . . . . . . . . . . . . . . 1.4 Main Characteristics of Heterogeneous Flows . . . . . . . . . . . . . 1.4.1 Time of Dynamic Relaxation of Particles . . . . . . . . . . 1.4.2 Time of Thermal Relaxation of Particles . . . . . . . . . . . 1.4.3 Stokes Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4.4 Particle Concentration . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 Classification of Heterogeneous Turbulent Flows . . . . . . . . . .
. . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . .
1 1 1 4 6 7 9 9 11 12 13 13 15 17 17 18 18 19 22
Mathematical Simulation of ParticleLaden Gas Flows. . . . 27 2.1 Preliminary Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2.2 Special Features of Simulation of Heterogeneous Flows of Different Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.3 Description of Motion of Solid Particles Suspended in Turbulent Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 2.3.1 Lagrangian Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 2.3.2 Eulerian Continuum Approach . . . . . . . . . . . . . . . . . . . . . 39
X
3
4
Contents
2.4
Description of Motion of Gas Carrying Solid Particles . . . . . . . . 2.4.1 Algebraic Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.2 One-Parameter Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.3 Two-Parameter Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4.4 Methods of Direct Numerical Simulation . . . . . . . . . . . . .
Physical Simulation of ParticleLaden Gas Flows. . . . . . . . . . 3.1 Preliminary Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Laser Doppler Anemometry and its Advantages . . . . . . . . . . . . . 3.3 Special Features and Objectives of Experimental Studies of Heterogeneous Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4 Special Features of Studies of the Behavior of Solid Particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.1 Optimization of LDA Parameters . . . . . . . . . . . . . . . . . . . . 3.4.2 Measurement of the Velocities of Polydisperse Particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4.3 Monitoring of the Accuracy of the Results . . . . . . . . . . . . 3.4.4 Measurement of the Relative Concentration of Particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5 Special Features of Studies of the Effect of Solid Particles on Gas Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5.1 Estimation of Cross-talk: Methods of Signal Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5.2 Estimation of the Efficiency of Amplitude Selection of Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6 Experimental Apparatuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6.1 Experimental Setup for Studying Upward Flows of Gas Suspension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6.2 Experimental Setup for Studying Downward Flows of Gas Suspension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.6.3 The Choice of Particle Characteristics: An Example . . .
42 45 46 48 48
51 51 52
55
57 58
61 67
68
75
75
78 85
86
87 88
ParticleLaden Channel Flows91. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Preliminary Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 4.2 The Behavior of Solid Particles and Their Effect on Gas Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 4.2.1 Averaged Velocities of Gas and Particles . . . . . . . . . . . . . 92 4.2.2 Fluctuation Velocities of Gas and Particles . . . . . . . . . . . 98 4.2.3 The Effect of Particles on the Energy Spectrum and Scales of Turbulence of Gas . . . . . . . . . . . . . . . . . . . . . 107 4.2.4 Generalization of Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
5
4.3
Contents
XI
Simulation of the Effect of Particles on Turbulent Energy of Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 4.3.1 The Dissipation of Turbulent Energy by Small Particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 4.3.2 The Generation of Turbulent Energy by Large Particles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 4.3.3 The Effect of Particles on Turbulent Energy of Gas . . . . 121
ParticleLaden Flows Past Bodies. . . . . . . . . . . . . . . . . . . . . . . . . . 127 5.1 Preliminary Remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 5.2 A Flow with Particles in the Region of the Critical Point of a Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 5.2.1 Theoretical Investigations . . . . . . . . . . . . . . . . . . . . . . . . . . 129 5.2.2 Experimental Investigations . . . . . . . . . . . . . . . . . . . . . . . . 138 5.3 A Particle-Laden Flow in the Boundary Layer of a Body Subjected to Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 5.3.1 Theoretical Investigations . . . . . . . . . . . . . . . . . . . . . . . . . . 151 5.3.2 Experimental Investigations . . . . . . . . . . . . . . . . . . . . . . . . 156 5.4 The Body Drag in Particle-Laden Flows . . . . . . . . . . . . . . . . . . . . 165
Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169. . . . . . . . . . . . . . . . .
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187. . . . . . . . . . . . . . . . . . . . . .
http://www.springer.com/978-3-540-68053-6