Principles of Powder Mechanics

Preface

Acknowledgments

Chapter 1. Introduction

Three Principles

Some Definitions

Materials

Plan of the Monograph

Packings

Elementary Statics

Measurement of Powder Properties

Flow Patterns

Kinematics

Discussion

Selection of References to Particle Size and Shape

Chapter 2. Packings

Bulk Density

Wall Effect

Closely Graded Spherical Granules

Closely Graded Irregular Granules

Binary Granular Mixes

Mixtures

Graded Cohesive Powders

Coordination Numbers

Radial Distributions

Angles of Repose

Graded Granular Powders

Conical Heap a3

Two-Dimensional Slope a2

Crater Angles áâ

Instantaneous Free Surface a,

Cohesive Powders

Compaction and Moisture Content

Discussion

Chapter 3. Elementary Statics

Plane Stress Analysis

The Mohr Circle Diagram

The Principal Planes

The Equations of Equilibrium

Coulomb Powders

The Mobilization of Friction

The Directions of Sliding

The Principal Stresses in Plastic Equilibrium

Active and Passive Rankine states

The Pressures on a Smooth, Vertical Retaining Wall

Active and Passive Failure

The Shape of a Self-Supporting Dome over a Circular Aperture

Arching in Shallow Beds

Arching in Deep Beds

Janssen's Equation for the Pressure in a Tall Bin

Practical Observations

Experimental Evidence Relating to Janssen's Equation

Pressures Measured in Hoppers

Discussion

Chapter 4. Measurement of Powder Properties

Friction and Cohesion

Tensile Strength

Shear Strength

Dilatancy

Ready Sliding

The Shear Cell

Yield Locus

The Critical Voids Ratio

Summary

Wall Friction and Adhesion

Discussion

Chapter 5. Flow Patterns and Segregation

Introduction

Flow Patterns

Experimental Methods

Scaling of Models

Discharge of a Powder from a Cylindrical Bin

Discharge of a Granular Powder from a Flat Bin

Surfaces of Sliding

Discharge of Beads from a Conical Hopper

Flow Regulators

Flow through Chutes

Discussion

Segregation and Percolation

Size Segregation

Density Segregation

Percolation

Chapter 6. Kinematics

Introduction

Dilatant Waves

Free-Fall Arch

Stream Tubes

Radial Flow

Angles of Approach

Discussion

Energy Dissipation Postulate

Minimum Energy Theorem

The Statistically Empty Space

Mass Flow Rate in a Symmetrical Wedge

Mass Flow Rate in an Asymmetrical Wedge

Mass Flow Rate in a Cone

Mass Flow Rates

Some General Observations

Experimental Method

Analysis of Data

Effect of Width of Vessel

Flow through Circular Apertures from Wide Vessels

Flow through Jets

The Effect of Restricting Air Entry

Flow from Flat-Bottomed Vessels through Central Slots

Two Regimes of Flow from troughs through Slots

Blocked and Obstructed Apertures

The Empty Annulus

Blocked and Obstructed Apertures

Discussion

Chapter 7. Conclusion

Bibliography

Index of Names

Subject Index

Other Titles in the Series