Surface depression with double-angle geometry during the discharge of grains from a silo

Surface depression with double-angle geometry during the discharge of grains from a silo When rough grains in loose packing conditions are discharged from a silo, a conical depression with a single slope is formed at the surface. We observed that the increase of volume fraction generates a more complex depression, characterized by two angles of discharge: one at the bottom similar to the angle of repose and a considerably larger upper angle. The change in slope appears at the boundary between a dense stagnant region at the periphery and the central flowing channel formed over the aperture. Since the material in the latter zone is always fluidized, the flow rate is unaffected by the initial packing of the bed. On the other hand, the contrast between both angles is markedly smaller when smooth particles of the same size and density are used, which reveals that high packing fraction and friction must combine to produce the observed geometry. Our results show that the surface profile helps to identify by simple visual inspection the packing conditions of a granular bed, being useful to prevent undesirable collapses during silo discharge in industry. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Physical Review E American Physical Society (APS)

Surface depression with double-angle geometry during the discharge of grains from a silo

Preview Only

Surface depression with double-angle geometry during the discharge of grains from a silo

Abstract

When rough grains in loose packing conditions are discharged from a silo, a conical depression with a single slope is formed at the surface. We observed that the increase of volume fraction generates a more complex depression, characterized by two angles of discharge: one at the bottom similar to the angle of repose and a considerably larger upper angle. The change in slope appears at the boundary between a dense stagnant region at the periphery and the central flowing channel formed over the aperture. Since the material in the latter zone is always fluidized, the flow rate is unaffected by the initial packing of the bed. On the other hand, the contrast between both angles is markedly smaller when smooth particles of the same size and density are used, which reveals that high packing fraction and friction must combine to produce the observed geometry. Our results show that the surface profile helps to identify by simple visual inspection the packing conditions of a granular bed, being useful to prevent undesirable collapses during silo discharge in industry.
Loading next page...
 
/lp/aps_physical/surface-depression-with-double-angle-geometry-during-the-discharge-of-7454TWuU4s
Publisher
American Physical Society (APS)
Copyright
Copyright © ©2017 American Physical Society
ISSN
1539-3755
eISSN
550-2376
D.O.I.
10.1103/PhysRevE.96.022901
Publisher site
See Article on Publisher Site

Abstract

When rough grains in loose packing conditions are discharged from a silo, a conical depression with a single slope is formed at the surface. We observed that the increase of volume fraction generates a more complex depression, characterized by two angles of discharge: one at the bottom similar to the angle of repose and a considerably larger upper angle. The change in slope appears at the boundary between a dense stagnant region at the periphery and the central flowing channel formed over the aperture. Since the material in the latter zone is always fluidized, the flow rate is unaffected by the initial packing of the bed. On the other hand, the contrast between both angles is markedly smaller when smooth particles of the same size and density are used, which reveals that high packing fraction and friction must combine to produce the observed geometry. Our results show that the surface profile helps to identify by simple visual inspection the packing conditions of a granular bed, being useful to prevent undesirable collapses during silo discharge in industry.

Journal

Physical Review EAmerican Physical Society (APS)

Published: Aug 8, 2017

There are no references for this article.

Sorry, we don’t have permission to share this article on DeepDyve,
but here are related articles that you can start reading right now:

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off