Industrial and Management Systems Engineering

 

Date of this Version

6-2012

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Industrial and Management System Engineering, Under the supervision of Professor Ram Bishu. Lincoln, Nebraska: May, 2012

Copyright (c) 2012 Pourya Fasounaki

Abstract

Keeping inventory record of packed grains in silos poses challenges since the bulk material’s different segments do not discharge uniformly, leading to formation of random peaks and valleys on the surface. To facilitate obtaining accurate volume measurement of the grains by taking into account this non-linear behavior on the surface, laser or plumb-bob level-sensing devices are employed at different part of the surface to probe the level of material under those regions.

The main goals of this research is to study the behavior of granular material in silo while discharging downward and by doing so, differentiate certain flow patterns formed during this process which could be important in predicting granular materials’ behavior on the surface. In order to conduct this thesis study, three unique numerical discharge models were built with two types of granular material and assigned to these, were the material/mechanical properties of polyethylene plastic and corn kernels separately.

Validation procedures were conducted (grain volume measurements) by setting up a physical silo in the lab and monitoring center and side discharge developments for real polyethylene and maize grains, sequentially. The differences in results of numerical and lab discharge were small and large, depending on the materials used, as well as the type of discharge process performed (center or side). At the end, reruns of models were carried out with improved input values.

Advisor: Ram R. Bishu