Interfacial area concentration in gas-liquid metal two-phase flow

Abstract

The characterization and modelling of the flow features in gas and heavy liquid metal two-phase flow are required for the development of next generation nuclear reactor systems. In this study, the past experimental studies performed in the gas-liquid metal two-phase flow are reviewed, and the void fraction and interfacial area concentration (IAC) database taken in the N2-Pb/Bi (nitrogen and lead/bismuth eutectic alloy) two-phase flow in a vertical circular flow channel are collected. In order to obtain the flow characteristics of the gas-liquid metal two-phase flow, the experimental data of the N2-Pb/Bi two-phase flow are compared with experimental data of the air-water two-phase flow. The void fraction gradient along the height (namely the flow direction) and the bubble diameter in the N2-Pb/Bi two-phase flow are found to be much larger than those in the air-water two-phase flow. These two unique flow characteristics can be explained, respectively, by the large density and surface tension of the Pb/Bi eutectic alloy in the N2-Pb/Bi two-phase flow. This study also reviewed the available IAC correlations and found that so far no IAC correlation has been developed for the gas-liquid metal two-phase flow. So, the available major IAC correlations for air- and steam-water two-phase flows are collected and compared with the collected experimental data of the N2-Pb/Bi two-phase flow. The comparison shows that these IAC correlations cannot give reliable predictions for the experimental data of the N2-Pb/Bi two-phase flow. So, a new IAC correlation has been developed based on the experimental data of the N2-Pb/Bi two-phase flow by taking into account the properties and flow characteristics of the two phases. The newly-developed IAC correlation can satisfactorily predict the experimental data of the N2-Pb/Bi two-phase flow with the mean relative error of 0.0609.