ARTICLE:

• MEASURING HOLD-UP AND CONVECTIVE TRANSPORT IN STRUCTURED PACKINGS FOR HEAT AND MASS TRANSFER USING X-RAY TOMOGRAPHY  download article

B. Mahr
University of Hanover, Hanover, Germany

Dieter Mewes
University of Hannover, Institut fur Verfahrenstechnik (Process Engineering), Callinstr. 36, 30167 Hannover, Germany

ABSTRACT

In the present study, X-ray tomography and radiography are used to investigate two-phase flow in structured packings for heat and mass transfer. In addition, a contrast agent is used as a tracer to visualize streamlines and mixing within the liquid phase. X-ray radiography is used to non-invasively image liquid hold-up distribution in a column with Mellapak 250.Y (PP) structured packing in counter-current operation of water and air. The high spatial resolution of 300μm allows to detect hold-up peaks of only a few millimetres height. A quasi two-dimensional set-up with two sheets of structured packing material is used to investigate radial spreading of liquid via X-ray radiography. Film thickness on the packing is imaged. By the tracer technique, with sodium iodide for contrast enhancement, it is shown that the developed film flows at an angle of ±23° to the vertical. Little mixing between the sheets of packing is observed. X-ray tomography is employed to measure phase distribution in a column with structured packing. Again, a contrast enhancing tracer is used to visualize mixing and spreading. The results demonstrate how X-ray imaging with contrast agent as tracer allows to gain new insights into fluid dynamics in porous structures.

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