Development of Gas-Liquid Two-Phase Flow Measurement Method Using Multi-View Camera System

Abstract

Although there exist several methodologies to measure gas-liquid two-phase flows, such as wire-mesh sensors and X-ray CT, a direct measurement of bubble coalescence and breakup is difficult due to their multidimensionality and unsteady nature. However, a comprehensive understanding of gas-liquid two-phase flow under such conditions is essential for predicting the effectiveness of scrubbing, i.e. to remove fission products during severe accidents in nuclear power plants. The objective of this study is to develop a new methodology to directly measure and analyze gas-liquid two-phase flow under high void, churn-turbulent regime in a large space through an initially stagnant pool of water. For this purpose, a new technique to measure two-phase flow using multi-view images has been developed. A total of 29 synced cameras housed in a water-proofed casing were placed inside a test section with an inner diameter of 1.5 m and a height of 4 m, to construct a multi-view camera system. The test section was filled with water up to a height of 2 m, and images were taken as air was supplied from a cylindrical nozzle at the bottom with flow rates of 500 to 2000 L min-1. The cameras were calibrated, and an algorithm was developed to reconstruct the air flow in 3D voxel space. The results suggest that the developed technique, together with data assimilation and other techniques, could be applicable for measuring gas-liquid two-phase flow under churn-turbulent regime in a large space. In this paper, the progress of the development of the multi-view measurement and analysis technique, and the results of preliminary investigations are discussed.