Two-phase flow in a horizontal mini-size impacting T-junction with a rectangular cross-section

An experimental and analytical study was conducted in order to investigate the phase redistribution during two-phase flow in a horizontal mini-size impacting T-junction. The inlet and outlet sides of the junction have rectangular cross-sections with a 1.87-mm height and a 20-mm width, and the entire test section was machined in an acrylic block to facilitate flow visualization. Air-water mixtures at 200 kPa (abs) and room temperature were used as the test fluids. Four flow regimes were identified visually in the fully-developed region of the inlet side of the junction (bubbly, plug, chum, and annular) and a flow-regime map covering the ranges of gas and liquid inlet superficial velocities of 0.04 <= J(G1) <= 10 m/s and 0.02 <= J(L1) <= 0.7 m/s, respectively, was generated. Phase redistribution experiments were conducted covering all four inlet flow regimes. Models are proposed for predicting the average gas and liquid velocities, and the void distribution in the fully-developed region of the inlet side of the junction and the results from these models were used as input to the phase redistribution model. Good agreement in terms of magnitude and trend was obtained between the present experimental data and a modification of an existing model. (C) 2012 Elsevier Ltd. All rights reserved.