Bubble columns dynamics inferred from the motion of a radioactive tracer followed by axially aligned detectors

Bubble column dynamics can be properly studied with advanced velocimetry techniques, like radioactive particle tracking (RPT). However, sophisticated methods are scarcely used in the industrial environment; simpler methodologies like nuclear gauge scanning are generally preferred even if they provide more limited information. This work explores the feasibility of inferring information of the underlying dynamics in bubble columns, using a set of axially aligned detectors (AADs). The AADs scan simultaneously different column heights when a unique radioactive tracer is left free within the examined vessel, thus avoiding the cumbersome calibration required for RPT. The combined response of the AADs is analyzed by means of a data mining procedure to determine quantitative indexes related to the underlying flow regime.

• Axially aligned detectors (AADs) allows characterization of bubble columns’ dynamics. • Approximate tracer axial trajectories can be reconstructed from the AADs response. • Tracer path is analyzed by data symbolization to diagnose flow regime transitions. • Residence time of the tracer at different column regions is estimated. • The influence of liquid viscosity on the tracer trajectories is studied.