A High Speed Scanning Electron Beam X-ray Tomography System for Optically Opaque Flows*

Computational fluid dynamics tools are becoming increasingly capable of modelling complex multiphase flows with the advancement of modern computing and high-fidelity codes. As these codes become increasingly capable, the need to verify and validate the physical models though accurate experimental measurements with well characterized uncertainty becomes ever more important. Development of a true 3D (initially 4-plane) scanning electron beam X-ray tomography system was undertaken to image and measure void fraction distributions of optically opaque flows. A 20 kW electron beam that can be rapidly focused and deflected, thus varying X-ray source location, allows us to generate limited-angle projection data of an object of interest at O(kHz) rates. Limited-angle tomography with reduced artifacts is achieved using a statistical reconstruction algorithm to produce cross-sectional images of flows. Evaluation of the system performance is done via the use of a static and a dynamic phantom emulating bubbly flow. Preliminary data of a bubbly flow are also presented.