Hydrodynamic investigations of bubbly flow in periodic open cellular structures by ultrafast X-ray tomography


Hydrodynamic investigations of bubbly flow in periodic open cellular structures by ultrafast X-ray tomography

Wagner, M.; Zalucky, J.; Bieberle, M.; Hampel, U.

Packed bubble columns are common multiphase flow reactor types in chemical engineering. Regarding process efficiency, high mass transfer rates are desirable. Especially, periodic open cell structures (POCS) are supposed to increase the interfacial density and hence the mass transfer in multiphase reactions. At the Helmholz-Zentrum Dresden – Rossendorf an ultrafast X-ray imaging technique is used to analyze a wide range of multiphase flow scenarios. A rotating electron beam induces X-ray generation on two targets which enables to produce up to 8000 cross-sectional images per second from two measurement planes with a spatial resolution of about 1 mm. We applied this tomography system in an experimental setup including POCS. In the threedimensional tomography data sets, bubbles were identified and characterized. For different gas flow rates, we determined the axial velocities of the gas-phase, bubble size distributions, bubble aspect ratios and timeaveraged gas hold-ups. We compared these results with measurements in an unpacked-bubble column. The results show that the POCS have a significant influence on the hydrodynamics, especially regarding the interfacial area density.

Keywords: ultrafast X-ray CT; two-phase flow; packed bubble column

  • Contribution to proceedings
    10th Pacific Symposium on Flow Visualization and Image Processing, 15.-18.06.2015, Napoli, Italia
  • Poster
    10th Pacific Symposium on Flow Visualization and Image Processing, 15.-18.06.2015, Napoli, Italia

Permalink: https://www.hzdr.de/publications/Publ-22861
Publ.-Id: 22861