Fast Computed Tomographic Imaging within Turbulent Fluidised Beds

P R P Bruneau1, R F Mudde1 and T H J J van der Hagen2

1Kramers Laboratorium voor Fysische Technologie, TU Delft, Prins Bernhardlaan 6, 2628 BW Delft, The Netherlands. P.R.P.Bruneau@klft.tn.tudelft.nl

2Interfacultair Reactor Instituut, TU Delft, Mekelweg 15 2629 JB Delft, The Netherlands.

ABSTRACT

ECT (Electrical Capacitance Tomography) and X / γ-ray computed tomography (CT) have become popular measurement techniques in multiphase flow research due to their non-intrusive and full field capabilities. However, resolution in both spatial and temporal senses remains problematic and the contrasting capabilities of ECT and CT are well documented. Simply stated, ECT provides high temporal resolution at the expense of spatial resolution, the converse being true for CT. As a result, most previous applications of CT techniques to fluidisation have been restricted to time averaged measurements. In this work, the application of γ-ray CT to fluidised systems is re-examined, specifically the reduction of sampling times and the visualization of evolving structures within turbulent fluidised beds. A fan beam configuration using static 100 mCi 137Cs sources is evaluated by performing simulated measurements of the void fraction distribution within a model fluidised bed. Results for both three and five-source systems are presented which indicate that spatial and temporal resolutions of 10 mm and 10 ms are achievable.

Keywords Fluidised-bed, tomography, gamma-ray, x-ray