Development and assessment of a microwave void-fraction measurement system

The proof of concept of a non-invasive reflection-type void measurement system using microwaves is developed. Before constructing the instrument, governing equations are used to perform numerical simulations of different electrical components (reflectometer, antenna, etc.). Design and preliminary calibrations are performed based on these simulations. The results are then used to manufacture a setup that is installed on a Plexiglas vertical tube containing known volumetric fractions of gas in water at atmospheric conditions. The amount of injected gas and water are accurately controlled and the response of the system is compared with the simulations which confirm the suitability of such a system to study two-phase water-air mixtures.