Towards a one parameter equation for a silo discharging model with inclined outlets

VILLAGRÁN OLIVARES, MARCELA C.; BENITO, JESICA G.; UÑAC, RODOLFO O.; VIDALES, ANA M.

POWDER TECHNOLOGY

ELSEVIER SCIENCE SA

Año: 2018 vol. 336 p. 265 - 272

0032-5910

Experiments on the discharge of a silo with an inclined outletare performed for three types of seeds. The angle of inclination isvaried to cover the complete range from 0º to 90º. The theoreticaldescription of the flow rate behavior as a function of the aperture angleis achieved taking into account the two types of regimes present in theproblem: funnel and mass flow. The former is assumed to be dominated byarch formation- destruction and, consequently, a free falling down of theparticles from the arch dome is able to predict the experimental behaviorthrough the addition of just one parameter closely related to thegeometry of the arch. The second regime is described through a radialvelocity picture for the flow streams close to the silo aperture and anumerical integration allows calculating the expected flow with goodresults. Finally, with the hypothesis that radial velocity can always beused as a good approximation for flow streams, an equation valid for allthe range of angles is derived with the inclusion of just one parameterrelated to the drag force exerted by the flow on the particles. Thechallenge of one parameter equation for describing the mass flow rate ina wedged hopper is achieved and discussed.