Assessment of the flow properties of crushed grain products depending on the granulometric condition

Thomas Hoffmann

Abstract


Several methods were developed to assess the flowability of bulk material. Jenike introduced flowability values to
assess the flowability of bulk material like mineral raw material under given loads. A method developed by Carr uses
several granulometric parameters to describe the flow properties without influence on the load. The aim of the own study
was to evaluate the recommendations of Jenike and Carr regarding to their application onto crushed grain. Therefore
measurements with grainy and powdery grain products were carried out to determine flow properties regarding Jenike and
Carr. Additionally unloading tests with a level model silo were performed to find out the influence of the outlet diameter.
The evaluations of the flow properties according to Jenike and Carr deliver partially different textual evaluations. The
flowability to Jenike and the flow index according to Carr drop abruptly in the range Q3(0.2 mm) = 5% ... 20%. This shows
that the flow properties are mainly influenced by their share of cohesive fines. A classification of the flow properties
according to Jenike is more realistic for crushed grain.



Keywords


crushed grain, flow properties, Jenike shear cell, Carr index

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