EXPERIMENTAL INVESTIGATION OF TWO-PHASE BUBBLY FLOW PRESSURE DROP ACROSS A HORIZONTAL PIPE CONTAINING 90° BENDS

Two-phase gas–liquid pressure drop was experimentally investigated in a 9 m long, 50.8 mm internal diameter, horizontal test section containing 2 closely spaced 90° bends. Bubble and dispersed flow regimes were achieved at superficial liquid and gas velocities that were varied from 3.50 to 5.42 m/s, and 0.10 to 1.25 m/s, respectively. Single-phase and two-phase flow pressure drop tests were performed to evaluate major and minor loss coefficients. The Lockhart–Martinelli parameters were modified through the addition of a minor loss term, and results were compared with Chisholm’s turbulent-turbulent gas–liquid pressure drop model. Three different pipe configurations were evaluated. They consisted of a single straight pipe, a straight pipe with a single 90° bend, and straight pipe with two 90° bends. Both Blasius’ and Prandtl’s smooth pipe models were evaluated to predict the two-phase frictional losses, while single- and two-phase minor loss coefficients were tested with varying degrees of effectiveness. Ov...