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The novel traveling fluidization column, designed and built to assure identical operating conditions, was deployed to compare alternate experimental measurement techniques for hydrodynamic characterization of gas-fluidized beds. This paper compares measurements of particle velocity obtained by radioactive particle tracking (RPT – non-invasive at the Ecole Polytechnique), positron emission particle tracking (PEPT – non-invasive at University of Birmingham), optical fibre probes (invasive at UBC) and borescopic high speed particle image velocimetry (invasive at PSRI) carried out with FCC particles of mean diameter 107 μm. All of the techniques provided similar trends with respect to time-average particle velocity profiles, but significant differences were observed in some cases. Analysis of the results, focusing on the physical principles of each measurement technique, provides valuable insights into the reasons for the observed discrepancies. The results also add to a unique hydrodynamic database for validation of CFD and other mechanistic models.© 2015 Elsevier B.V. All rights reserved

The novel “travelling fluidized bed” (TFB), operated under identical conditions, was deployed to compare alternate experimental measurement techniques for the investigation of solid motion in gas-fluidized beds operating in the square-nosed slugging regime. Measurements of particle velocity obtained by radioactive particle tracking (RPT – non-invasive at the Ecole Polytechnique de Montréal), positron emission particle tracking (PEPT – non-invasive at University of Birmingham), optical fibre probes (invasive at UBC) and borescopic high speed particle image velocimetry (invasive at PSRI) are compared for sand particles of mean diameter 292 μm. Significant differences between the time-average radial profiles of particle velocity are observed in many cases. The results provide valuable insights on the merits and challenges of advanced particle velocity measurement techniques.© 2015 Elsevier B.V. All rights reserved

No abstract

Particle tracking methods using emitted radiation are attractive for following motion in opaque systems such as granular materials. Leading examples are Positron Emission Particle Tracking (PEPT) and Radioactive Particle Tracking (RPT). The application of such techniques sometimes requires the use of tracer particles which differ in size, density and/or shape from the particles of interest. This study investigates the extent to which such differences affect the result of the study by using the open source MFIX-DEM software to model particle motion in the travelling fluidized bed experiments. The results are compared with previously reported experimental studies using both PEPT and RPT. Consistent numerical results were obtained for both PEPT and RPT tracer particles. In determining averaged velocities using such techniques, there is a choice to be made between averaging velocities of particles crossing a virtual plane over a period of time (the "face-average" approach) or those passing through a defined volume over time (the "volume-average" approach). The differences between results obtained with these two approaches are shown to be significant in this case, for both computation and experiment.