MEASUREMENT OF DISTRIBUTION OF LOCAL VOID FRACTION IN TWO-PHASE FLOW BY X-RAY COMPUTED TOMOGRAPHY.

A new X-ray CT scanner system, using time-averaged projection data (X-ray beam intensity), called Advanced Computed Tomography System (ACTS), was developed for measuring accurately the local void fraction distribution in the two-phase flow of various flow configurations and patterns. A horizontal circular tube and a 4 multiplied by 4 rod bundle were used as test sections. Air-water mixtures were used as test fluids. The local void distribution measured by ACTS and that measured by an impedance probe were compared. The agreement was excellent for tested flow patterns (bubbly flow, slug flow, plug flow and annular flow) both in the horizontal tube and in the 4 multiplied by 4 rod bundle. It was concluded that ACTS can be applied to the measurement of local void distribution in any flow patterns and in any flow channel configurations.