Beyond the Beverloo rule and a new universality for silo discharge

MARCOS A. MADRID; J.R. DARIAS; LUIS A. PUGNALONI

Santiago de Chile

Workshop; SOUTHERN WORKSHOP ON GRANULAR MATERIALS; 2015

Universidad de Chile

The Beverloo rule obteined by dimensional analysis on the dischage of a silo shows that the flow rate is independent of the height of the granular column. However, a more straiking finding from the experiments is that the number of particles flown per unit time is virtually independent of the material properties of the grains [1,2]. Recent works have shown that this apparently universal flow rate is not followed by granlars with low friction or immersed in a fluid [3,4]. We show that forced flow using a piston can also break this universality: different materials respond differently. Interestingly, a new universalily is displayed by the disipated power scaled with the average pressue in the system.[1] Beverloo et al., Chem. Eng. Sci., Vol 15, 1961, pp 260-269.[2] Mankoc et al. Granular Matter, Vol. 9, Issue 6, 2007, pp 407-414.[3] Kondic, Granular Matter, Vol. 16, Issue 2, 2014, pp 235-242.[4] Durian et al. Pap. Phys. Vol.6 no.2, 2014.