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Title: Studies of granular flow down an inclined chute. Final technical report

Abstract

An inclined chute facility and its associated diagnostics has been developed and utilized to study the flow of granular materials. A variety of flow regimes and flow phenomena were observed. Fully developed flows were observed over a bumpy base for a range of slopes. Under some conditions, these flows were dominated by friction and under other conditions, collisions played a dominant role. A variety of unsteady flows were also observed. These include decelerating flows, accelerating flows, and wavy (periodic) flows. The characteristics of the base strongly influenced the flow regime and flow dynamics.

Authors:
Publication Date:
Research Org.:
Florida Univ., Gainesville, FL (United States)
Sponsoring Org.:
USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States)
OSTI Identifier:
415976
Report Number(s):
DOE/PC/90182-T20
ON: DE97050216
DOE Contract Number:
AC22-91PC90182
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Jun 1996
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; GRANULAR MATERIALS; SOLIDS FLOW; PROGRESS REPORT; FRICTION; COLLISIONS; INCLINATION; EXPERIMENTAL DATA; VELOCITY

Citation Formats

Hanes, D.M.. Studies of granular flow down an inclined chute. Final technical report. United States: N. p., 1996. Web. doi:10.2172/415976.
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Hanes, D.M.. Studies of granular flow down an inclined chute. Final technical report. United States. doi:10.2172/415976.
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Hanes, D.M.. Sat . "Studies of granular flow down an inclined chute. Final technical report". United States. doi:10.2172/415976. https://www.osti.gov/servlets/purl/415976.
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@article{osti_415976,
title = {Studies of granular flow down an inclined chute. Final technical report},
author = {Hanes, D.M.},
abstractNote = {An inclined chute facility and its associated diagnostics has been developed and utilized to study the flow of granular materials. A variety of flow regimes and flow phenomena were observed. Fully developed flows were observed over a bumpy base for a range of slopes. Under some conditions, these flows were dominated by friction and under other conditions, collisions played a dominant role. A variety of unsteady flows were also observed. These include decelerating flows, accelerating flows, and wavy (periodic) flows. The characteristics of the base strongly influenced the flow regime and flow dynamics.},
doi = {10.2172/415976},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Jun 01 00:00:00 EDT 1996},
month = {Sat Jun 01 00:00:00 EDT 1996}
}
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Technical Report:
View Technical Report (5.56 MB)
DOI:  10.2172/415976
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  • The driving force for the granular flow in the experimental region is gravity. The vehicle which re-circulates this flow is an 46 cm Corra-Trough belt conveyor manufactured by Buck-El, Inc. A drawing of this conveyor is shown in Figure 3. Entrance and exit chambers were designed to route the flow between the chute and the conveyor. Both devices had to be flexible because the position of the chute relative to the conveyor changes each time the angle of the chute is changed. Finally, to control the entering flow more accurately, an adjustable gate apparatus was constructed. The first step inmore » setting up the chute is angle adjustment. The granular material used in the experiments described in this report are technical quality glass spheres, three millimeters in diameter. These beads are produced by Cataphote, Inc. Cataphote lists the tolerances for the 3mm spheres at [plus minus]0.2 mm. The average mass of a single bead was measured to be 0.034 g which gives an average measured specific gravity of the glass at 2.42 g/cm[sup 3].« less

  • A preliminary series of experiments were run in order to examine the effects sidewalls have on the steady-state mass flow rate of granular material in a rectangular, inclined chute. These experiments also serve to assess the problems associated with the initial operation of the granular flow apparatus. Presumably, the friction between the sidewalls and the flowing material will slow the flow rate of that material. The relative effect of the sidewalls should decrease with increasing width for a given flow entrance condition. For instance, when the width of the chute is at a minimum (one grain diameter), the sidewalls willmore » have a maximum frictional effect. And as the width approaches infinity, the sidewalls will have a minimum frictional effect. It is desired to know at what chute widths the sidewall effects will reasonably approach this minimum, if this condition can even be approached with the existing apparatus. The relationship between chute width and flow rate will be important to know during more involved experiments which will follow this initial investigation. These experiments will include the measurement of localized grain density, local velocity and individual grain dynamics (rotation and translation) and collisions. The secondary objective, to observe and correct problems with the system, is a more general and qualitative goal.« less

  • The driving force for the granular flow in the experimental region is gravity. The vehicle which re-circulates this flow is an 46 cm Corra-Trough belt conveyor manufactured by Buck-El, Inc. A drawing of this conveyor is shown in Figure 3. Entrance and exit chambers were designed to route the flow between the chute and the conveyor. Both devices had to be flexible because the position of the chute relative to the conveyor changes each time the angle of the chute is changed. Finally, to control the entering flow more accurately, an adjustable gate apparatus was constructed. The first step inmore » setting up the chute is angle adjustment. The granular material used in the experiments described in this report are technical quality glass spheres, three millimeters in diameter. These beads are produced by Cataphote, Inc. Cataphote lists the tolerances for the 3mm spheres at {plus_minus}0.2 mm. The average mass of a single bead was measured to be 0.034 g which gives an average measured specific gravity of the glass at 2.42 g/cm{sup 3}.« less

  • The dynamics of flowing granular material has been previously observed in inclined chutes. One of the questions arising from previous work regards the existence of fully developed, steady flows. Depending upon the friction or bumpiness of the chute base, experiments have indicated that under some conditions the flow appears to be steady and fully developed. While a truly fully developed flow can never be proven to exist in an experimental apparatus because of its finite length, apparent fully developed flows are observed to within reasonable experimental accuracy. The present series of experimental focuses on the existence of steady, fully developedmore » flows over a low friction, bumpy base.« less

  • A preliminary series of experiments were run in order to examine the effects sidewalls have on the steady-state mass flow rate of granular material in a rectangular, inclined chute. These experiments also serve to assess the problems associated with the initial operation of the granular flow apparatus. Presumably, the friction between the sidewalls and the flowing material will slow the flow rate of that material. The relative effect of the sidewalls should decrease with increasing width for a given flow entrance condition. For instance, when the width of the chute is at a minimum (one grain diameter), the sidewalls willmore » have a maximum frictional effect. And as the width approaches infinity, the sidewalls will have a minimum frictional effect. It is desired to know at what chute widths the sidewall effects will reasonably approach this minimum, if this condition can even be approached with the existing apparatus. The relationship between chute width and flow rate will be important to know during more involved experiments which will follow this initial investigation. These experiments will include the measurement of localized grain density, local velocity and individual grain dynamics (rotation and translation) and collisions. The secondary objective, to observe and correct problems with the system, is a more general and qualitative goal.« less