Consider the Density
Flow property evaluation of bulk materials
Summary: Since the methods for the evaluation of the flow properties according to Jenike and Carr mainly used today often result in misinterpretations, examinations with crushed grain were carried out. A comparison of the flow properties calculated on the basis of shear tests according to Jenike using the flow index according to Carr partly reveals considerable differences. The reason for this is the fact that the Jenike classification does not take the density into account. Therefore, it is more appropriate to use the outlet width required for the trouble-free discharge as a measure for fluidity. Results of theoretical analyses and calculations as well as experimental research findings provide a hyperbolic interrelation between outlet width and flowability as well as bulk material density. As the density effect is comprehensively examined, the results are generally valid and thus also applicable to mineral raw materials.
1 Introduction
In the past, flowability evaluation occurred according to easily determinable bulk material parameters, e.g. acc. to the slope angle. Further progress was made by experimental studies using silo models on the basis of which e.g. the minimum dimensions of the outlet port or the mass flow were determined. Theoretical foundations of dimensioning based on systematic material analyses and the analysis of stress and flow ratios in bulk materials have been existing, above all, since the second half of the past century [1]. Despite all, there are still uncertainties regarding the...
