Simulation Study on Multilayer Limited Angle Scanned Electron Beam X-ray CT Arrangements for Two-phase Flow Measurements

M. Bieberle, U. Hampel, H-M. Prasser, E. Schleicher

Institute of Safety Research, Forschungszentrum Dresden-Rossendorf e.V., POB 51 01 19, 01314 Dresden, Germany, Email: M.Bieberle@fzd.de

ABSTRACT

Recently, we presented a limited angle computed tomography approach that utilises a scanned electron beam X-ray source and provides up to 10000 cross sectional images per second. However, two problems arise when this measuring method is utilized for quantitative analysis of two-phase flows. Firstly, by acquiring a time sequence of cross sectional images of one plane in the flow no information about the volumetric structure of the flow can be obtained without knowing the different phase velocities. Secondly, the static arrangement of the X-ray focal spot path and the detector arc in one plane allows only a limited angular range from which projections are available. The missing data lead to artefacts in the reconstructed images which increase with the size and complexity of the imaged structures. For these reasons, simulation studies on different extended measurement arrangements with a two-dimensional beam deflection unit including multilayer imaging have been performed. The paper will be focused on these different arrangements and their influence on the phase structure recovery of two-phase flows.

Keywords limited angle X-ray CT, two-phase flow measurements