Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Reliable measurements form the basis for the understanding and modelling of two-phase flows. However, it is quite challenging to develop measurement techniques which achieve high spatial resolution and high temporal resolution at the same time. Electron beam x-ray CT is one technique, which provides cross-sectional images of an object of interest with about 1 mm spatial resolution at frame rates of up to 10,000 frames per second without influencing the flow. The method introduced here utilizes linear beam deflection which limits the angular range of the CT projections. With this method, we scanned a gas-liquid flow in an experimental flow loop operated at different liquid and gas flow rates. Electron-beam x-ray CT data was reconstructed and results compared with measurements of a wire-mesh sensor. The latter is a well-known intrusive measurement technique, which achieves comparable frame rates but at lower spatial resolution. As a novelty we implemented two-plane limited-angle electron beam x-ray tomography and are thus able to gain information about the phase velocities using cross-correlation data analysis Gas phase velocity information is a decisive parameter for accurate quantitative gas bubble size and gas fraction determination and is often missed in transmission tomography measurements.