Local Liquid Velocity Measurement in Trickle Bed Reactors (TBRs) Using the X-Ray Digital Industrial Radiography (DIR) Technique


This work describes the development of a new technique to measure local liquid velocity (VLL) for multiphase flows in trickle bed reactors (TBRs) (gas-liquid-solid system). In the studied TBR, the liquid phase is represented by water, gas by air and 3 mm expanded polystyrene beads as the solid packing. Three different superficial liquid velocities (VSL) and a constant superficial gas velocity (VSG) were used in the packed bed with an internal diameter of 4.25 cm. While the liquid is moving into the packed bed, tracking particles of 106-125 ?m diameter (16.45% difference) are injected. The movement of the tracking particles is monitored and digitally recorded by a complementary metal-oxide-semiconductor detector. In this experiment, x-rays were used as the radiation source. Four replications were made with fresh packing. Comparable observations can be found from other published techniques (i.e. magnetic resonance imaging). Results from this study indicate that, at VSL = 0.13 cm s-1, the measured V LL can reach up to 51 times that of its VSL, while for VSL = 0.27 cm s-1, the measured VLL reached up to 35 times higher than the VSL and for VSL = 0.39 cm s-1, the VLL reached up to 39.8 times higher than its VSL. Through statistical analysis, the implementation of such a method is found to be reproducible throughout the experiments. The mean per cent difference in the measured VLL was 10% and 5% for lower implemented VSL of 0.13 and 0.27 cm s-1, respectively. At higher VSL (0.39 cm s-1), the particle tracer was greatly distributed and carried away by the high liquid flow rate. The variance or the range of the measured VLL does not vary for all replications in every VSL, which confirms the reproducibility of the experimental measurements, regardless of the VSL. © 2014 IOP Publishing Ltd.


Nuclear Engineering and Radiation Science

Second Department

Chemical and Biochemical Engineering

Keywords and Phrases

Digital Industrial Radiography; Particle Tracking Velocimetry; Trickle Bed Reactor

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


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© 2014 Institute of Physics - IOP Publishing, All rights reserved.

Publication Date

01 Jan 2014