Synchrotron X-ray tomography of a Taylor bubble

A profound understanding of the transfer processes in capillary multiphase flow is of primary importance from the viewpoint of fundamental science as well as for practical design and operation of new chemical reaction devices. The desired flow regime in such small channel geometries is surface tension dominated Taylor bubble flow. Still today the lack of precise morphological data on such Taylor bubble capillary two-phase flows calls for the development of adequate measurement techniques providing the necessary spatial resolution for the investigation of the flow structures moving at moderate speeds. Experiments to reveal the shape of moving Taylor bubbles were performed at the ANKA synchrotron radiation source in Karlsruhe, Germany, in capillaries with a hydraulic diameter of dh = 2 mm. The careful examination of the bubble positions in the dataset enabled the generation of consecutive projection images necessary for application of a computerized tomographic reconstruction algorithm to reveal the cross-sectional shape of the Taylor bubble.