Two-phase flow redistribution phenomena in a large T-junction

Abstract

An experimental study into phase redistribution and pressure drop phenomena of two-phase (air-water) flow splitting in a horizontal upward reduced T-junction was carried out in an industrial-scale flow rig (inlet and run dia = 23 cm , branch dia = 10 cm ). Measurements were performed with inlet conditions in the stratified smooth, stratified wavy and bubbly flow regimes. The inlet liquid mass flow was varied between 75 and 225 m 3/h, the inlet quality was < 0.03%. The experiments reveal that the flow split phenomena observed in this large-scale T-junction, generally, do resemble those reported in the literature for smaller scales. Within that region, several models developed for smaller scales can be used to qualitatively describe the flow split and pressure drop at larger scales as well. It was observed that flow phenomena and regimes downstream of the junction still have impact on the flow split. In particular, the occurrence of pulsations in the branch causes a striking change in the phase redistribution behaviour within the junction. The transition from churn flow to pulsating churn could be determined quite distinctively by monitoring the time signals of the various pressure transducers along the flow path and their fast Fourier transforms.