Arching can occur during silo discharge of cohesive powders. In general this happens when the outlet size is not wide enough. Flow aid devices, such as aeration pads, are commonly used in the industry to achieve proper flow of cohesive materials. However, no design criteria are presently available for such kind of devices and, in particular, for the intensity of aeration to be used to avoid arching. Aim of this paper is the evaluation of the limiting aeration condition to produce the collapse of established arches. Experimental tests are carried out in an aerated flat bottom silo. The measured quantities are the aeration rate at arch collapse and the arch size. Powder permeability is characterized by fluidization experiments. Finally, a simplified model is proposed to assess on the prevailing physical phenomena.

The effect of aeration on arch collapsing in silo discharge

CANNAVACCIUOLO, Antonio;BARLETTA, Diego;DONSI', Giorgio;FERRARI, Giovanna;POLETTO, Massimo
2006

Abstract

Arching can occur during silo discharge of cohesive powders. In general this happens when the outlet size is not wide enough. Flow aid devices, such as aeration pads, are commonly used in the industry to achieve proper flow of cohesive materials. However, no design criteria are presently available for such kind of devices and, in particular, for the intensity of aeration to be used to avoid arching. Aim of this paper is the evaluation of the limiting aeration condition to produce the collapse of established arches. Experimental tests are carried out in an aerated flat bottom silo. The measured quantities are the aeration rate at arch collapse and the arch size. Powder permeability is characterized by fluidization experiments. Finally, a simplified model is proposed to assess on the prevailing physical phenomena.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11386/1631401
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