Quantitative ‘real-time’ imaging of multi-phase flow in ceramic monoliths

An extension of the RARE technique has been developed which acquires multiple images from a single radio-frequency excitation. This pulse sequence has been used to image, in real-time, gas flow through stagnant liquid within parallel-channel ceramic monoliths. From these images, gas-phase volume fractions, and distributions of gas bubble length and velocity as a function of gas flow rate (50-300 cm3 min−1) and channel size (300 and 400 channels per square inch, cpsi) are obtained directly. Increasing the gas flow rate increased the number of large bubbles and the average bubble velocity. A bimodal distribution in the bubble velocities was observed for flow within the larger channel size (300 cpsi) in contrast to a broad unimodal distribution characterizing two-phase flow within the smaller channel size (400 cpsi).