Investigation of three-dimensional two-phase flow using combined ultrafast X-ray tomography and hot-film anemometry

摘要

An experimental study on a generic three-dimensional two-phase flow around a flow obstruction has been carried out as a benchmark experiment for validation of two-phase CFD models. Therefore, ultrafast electron beam X-ray tomography was applied to disclose the bubble dynamics at different operating conditions at different axial positions upstream and downstream of the obstacle and combined with hot-film anemometry measurements. Selected results of the experiments were described, showing the effect of the gas superficial velocity on the flow field. It was shown that, on the one hand, a stagnation point develops upstream the obstacle and on the other hand a recirculation zone is formed downstream of it. These regions clearly affect the cross-sectional gas holdup as well as the resulting bubble size distribution. Furthermore, the measured liquid velocities were found to be influenced by the increasing gas content. A next step is an assessment of the accuracy of CFD codes for such flow conditions.