ERPT Tutorials
Stresses in Bins and Hoppers
(Use of Jenike's method for hopper design)
by Gabriel I. Tardos (City College of the City Univ of NY)
-- ERPT 992Q-Tardos,
Web Tutorials (not ERPT)
Design and Problems of Bins and Hoppers
The Jenike & Johanson Co. site has several publications:
--
www.jenike.com/pages/education/papers/papers.html
Ten Tips on Characterizing Bulk Materials
"Know Floe's Korner" in
The Particle Technology Forum's Newsletter provides key items and
practical considerations for making and interpreting measurements
to characterize bulk solids.
-- PTF News, Spring 2008, p 14,
by Lyn Bates, Shrikant Dhodapkar, and George Klinzing
Characterizing Powder Flow Properties
Stable Micro Systems Ltd. has patented a helical blade and developed a programmable
rotational drive. These were added to the vertical drive system provided by
Texture Technologies to create a Powder Flow Analyser. This instrument can move
through the powder in different ways. A sample of powder can be conditioned
by high speed blade rotation, then compacted to a specified stress to imitate
storage conditions. The rotor can then slice down through the powder with minimum
disturbance to the powder column by rotating and translating the blade down
a helical path that matches the blade's helical shape. The blade can then be withdrawn upward without rotation to measure the cohesion within the powder,
indicating how well the powder will flow after storage in a full silo.
--
www.texturetechnologies.com/Powder_Flowability.html.
Bulk Properties of Solids
Lecture notes by Prof. George Chase (Univ. of Akron)
--
Solids Course Outline Page (see Solids Notes 4, a PDF file)
Powder Bed Mechanics,
Lecture notes by Prof. George Chase (Univ. of Akron)
--
Solids Course Outline Page (see Solids Notes 9, a PDF file)
Plastic-Frictional Theories of Stress in Powder Beds
Sebastien Dartevelle (Univ. of Michigan) has created an extensive Web site called
The Granular Volcano Group.
Overview of Granular Theories, at
www.granular-volcano-group.org/granular_theory.html, has sections on
I. Introduction
II. Frictional Stress Formulation
III. Kinetic-Collisional Stress Formulation
1. Introduction
2. Granular kinetic Theory Facts: Granular Pressure and Granular Viscosity
3. Conservation of the Granular Temperature (or the Granular Fluctuating Energy)
4. Kinetic-collisional Stress Tensor
IV. Total Stress Tensor
V. Practical Application to Granular Flow: Grain concentration and Grain-size effect
Plastic-Frictional Theories of Stress in Powder Beds, at
www.granular-volcano-group.org/frictional_constitutive_equations.html, has sections on
I. Introduction
II. Stress space, Slip Planes, Mohr-Coulomb and von Mises stresses
1. Mohr-Coulomb case: a 2D representation of stress (particular case)
2. von Mises case: a 3D representation of stress (general case)
III. Plastic Potential Theory
IV. Dilatation, consolidation, yield locus, and critical state
1. Dilatancy
2. Consolidation
3. Yield locus and critical state
V. Constitutive Equations for Frictional Granular Flows
1. Beyond the extended von Mises Yield locus
2. Within the extended von Mises Yield locus
Bulk Solids in Silos
Several tutorials by Dr.-Ing. Dietmar Schulze
--- Fundamentals of bulk solids mechanics [Grundlagen der Schüttgutmechanik]
discusses the theory of shear stress in powders and describes several devices
that characterize the behaviour of powders under shear.
--- The storage of bulk solids in silos [Lagern von Schüttgütern in Silos]
explains wall pressure, different types of flow during discharge,
silo design, and the effect of outlet shape.
--- How to explore a silo [Die Untersuchung des Schüttgutflusses in Silos]
describes simple methods to check the flow profile in a silo.
--- Stresses in silos [Spannungen in Silos] is an introduction
to the distribution of stresses in silos during filling, standing, and discharge.
Several approaches for estimation are described, and methods for determining
the parameters of the powder are illustrated.
-- www.dietmar-schulze.de/info1e.html (English) /
www.dietmar-schulze.de/info1.html (Deutsch)
Non-Web Resources
Bulk Powder Handling Technology, The Design of Hoppers for Strength and Flow
by Centre for Industrial Bulk Solids Handling (Glasgow Caledonian Univ)
-- see ERPT's list of non-Web resources
