Visualisation of gas-liquid two-phase flow in opaque systems

Measurement and visualisation of two-phase flow is of high scientific and engineering relevance, for instance in mineral oil processing, chemical reaction engineering, and energy systems engineering. However, it is also a great challenge, because traditional visualisation tools, such as high-speed camera imaging and ultrasound measurements fail in multiphase systems. Tomographic methods are being considered as the key technology for multiphase flow visualisation, however, to date only few methods are suited because of stringent requirements for high spatial and temporal resolution. In particular, methods are sought, which can visualize two-phase flow in complex geometries. Examples are reactor vessels with internals, rod bundles of heat exchangers or nuclear fuel rod assemblies, but also porous media of fixed bed reactors or rock samples.
The presentation introduces two novel imaging modalities, namely wire mesh sensors and ultrafast X-ray tomography and their use in two-phase flow measurement in complex flow domain geometries. It will be shown, how gas-liquid flows can be visualized in fixed bed packings and flow channels intransparent walls.