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.