Angle of Repose

[Josh2008]

Not sure if this is the correct forum to be posting, but is my best guess.

The angle of repose is basically the angle that from the conical incline (formed from an unconsolidated bulk solid falling freely onto a horizontal plane) to the horizontal. I have learned that this is important in filling bins as it can create void space when the tip of the conical shape reaches the inlet of the bin.

Is it safe to assume that if the material flowing into the bin enters on a angle (or on the side) that the conical shape will follow the same pattern moving up its projected path?

Please see the picture for a better understanding.

So from the picture, the line with the arrow is the projected path of the material flowing into the bin. The yellow material is the pile of material at say Time 1. The orange and yellow is the pile at Time 2, and so on. The light blue space is the void space.

Now this is only my prediction. Can somebody elaborate, or point me in the direction of material online to read about this?


Second question is about potash. Is there available information on the angle of repose for this material? What about a range of bulk densities?

Thanks!

 

[ishvaaag]

http://www.bulk-store.ca/fert.html

POTASH: density = 1.124 tonne/m3 (70 P.C.F.).
Angle of repose = 30 degrees.

http://www.powderandbulk.com/resources/bulk_density/material_bulk_density_chart_p.htm

http://www.asiinstruments.com/technical/Material_Bulk_Density_Chart_P.htm

http://books.google.com/books?id=EH...onepage&q=bulk potash angle of repose&f=false

Google will give more answer. Other gives to 34 deg.

 

[fattdad]

geotechnical engineers don't like the term "angle of repose." We use the term "drained friction angle," which can be reflective of this pile slope, but not necessarily. . .

¡papá gordo ain’t no madre flaca!

 

[Josh2008]

Was my prediction for the conical or pile formation correct for the angled (projected) flow of material into the bin?

 

[edmy]

The angle of repose is achieved if the discharge point is close to the tip of the pile. The material could be piled at slopes shallower than the repose angle when there is a drop height. That is how I see the problem.

 

[BigH]

With silos, the "repose" angle might be affected by the proximity of the wall and wall friction - would not necessarily be that of an "open" or true repose of a pile (and dry vs moist would yet give different "repose" angles). Silo earth pressures have been discussed in a couple of other forums.