A new column collapse apparatus for the characterisation of the flowability of granular materials

• Published in: Powder technology Vol. 362; pp. 559 - 577
• Main Authors: Torres-Serra, J., Romero, E., Rodríguez-Ferran, A.
• Format: Journal Article Publication
• Language: English
• Published: Lausanne Elsevier B.V 15.02.2020; Elsevier BV
• Subjects: Calibration; Collapse; Dinàmica de fluids; Enginyeria dels materials; Fertilizers; Flow height; Flowability; Fluid dynamics; Free surfaces; Granular column collapse; Granular materials; Handling equipment; Load cells; Load distribution; Load distribution (forces); Materials granulars; Mathematical models; Morphology; Numerical models; Packaging; Particle image velocimetry; Pneumatic circuits; Run-out; Stress concentration; Talc; Three dimensional flow; Vacuum; Wall flow; Àrees temàtiques de la UPC; Particle image velocimetry; Granular column collapse; Flowability; Flow height; Run-out
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2019.11.080

The packaging industry is lacking a standard methodology to characterise the granular flow of a wide range of powders and grains in actual handling conditions. We present a new fully-instrumented granular column collapse apparatus for the experimental investigation of granular flow phenomena, by a quasi-two-dimensional set-up with novel features including: a lifting gate activated by a parallelogram mechanism for material release; a reversible pneumatic circuit to impose fluidised and vacuum conditions to the initial granular column; a set of load cells to monitor the basal load distribution during flow propagation; a 3D laser line profile sensor to scan the free surface morphology of the samples at rest; and a high-speed video recording set to capture near-wall flow visualisations and relevant kinematic measures by particle image velocimetry. The selected results on dry flows of oat flakes, copper sulphate fertiliser, and talc powder samples show their distinctive flow dynamics, indicating the good flowability of fertiliser compared to the poor flowability of talc. This research has implications for the selection and design of bulk solids handling equipment, and the calibration and validation of mechanical and numerical models. [Display omitted] •Granular column collapse apparatus is provided with redundant measuring techniques.•Results show different flowability for oats, fertiliser, and talc samples.•Load peak at high aspect ratio explains initial flow stage of downward acceleration.•Rotational kinetic energy is not negligible for flows of irregular shaped particles.•Pre-conditioning protocol enables us to reproduce bulk solids handling operations.