Study of flow of granular solids through horizontal orifices.

Abstract

A granular material is a conglomeration of discrete macroscopic particles. They have
properties different from those commonly associated with solids, liquid and gases. The
science of granular media has a long history with much engineering literature devoted to
understanding how to deal with these materials. Many of our industries rely on transporting
and storing granular materials. These include the pharmaceutical industries that rely on the
processing of various powders and pills, agricultural and the food processing industry where
various seeds, grains, and foodstuffs are transported and manipulated. The construction-based
industries are also included. Flow rate of granular solids through various sizes and shapes of
orifice is necessary so as to properly size the opening for flow control during transfer of
materials. The flow rate is key to calculate the kinematic parameters and velocity profile of
the solids in the column. In the past most of the work upon the flow rates of granular solids
have been the by-product of research into pressure distribution in hoppers or bins. In this
study, the variable of importance influencing the mass rate like orifice diameter, particle
diameter, particle density and angle of repose are studied and an empirical equation is
suggested relating them all.