Improvement of a wire-mesh sensor based on the bubble-wire collision kinematics

Abstract

While the wire-mesh sensor (WMS) has been widely used to measure the gas-phase distribution in gas–liquid two-phase flows with visually inaccessible conditions, there are still some issues to be improved such as the dependency on the bubble size and bubble-wire interaction pattern. In our previous work [Lee et al., Int. J. Multiphas. Flow, 139, 103,620 (2021)], we reported the development and validation of a set of two-layer WMS, which can simultaneously measure the velocity and size of O(10⁻²–10⁰) mm bubbles. In this study, considering the above-mentioned issues, we improve the measurement accuracy of the WMS, in particular, for relatively small (less than 2 mm) bubbles that tend to have asymmetric interactions with wires. To achieve this, we devised a new parameter to address the effect of non-uniform distance (proximity) to the nodes that are affected by the bubbles to be measured. Depending on the bubble-wire interaction (i.e., bubble size), we found that the characteristic time and length scales of the bubble vary, which are correlated with the proximity of bubbles to nodes with high electrical sensitivity. By implementing this into the algorithm, compared to the previous setup, the accuracy of measuring the averaged void fraction and velocity of bubbles increased by approximately 10 % and 20 %, respectively. We believe that the present approach will be quite useful in enhancing the measurement accuracy of other types (dual-set, for example) of wire-mesh sensors.