Gas-liquid two-phase flow patterns and pressure drop in a horizontal micro-rod bundle

Two-phase flow patterns and frictional pressure drop ina horizontal micro-r od bundle were experimentally studied, using air and water. The rod bundle was 23 cm long and consisted of seven 3.17-mm diameter rods arranged in a r ectangular pattern with 3.71-mm pitch. The rod bundle hydraulic diameter wa s 1.29 mm. The liquid and gas superficial velocities in the rod bundle cent er covered the 0.03-5.0 and 0.02-4.0 ms ranges, respectively. Six distinct flow patterns were observed: bubbly, plug/slug, froth, stratified-intermitt ent, annular-intermittent and annular. Complete stratification, bundle-wide or in individual subchannels, did not occur. The frictional pressure drops were strongly flow pattern-dependent. (C) 2000 Elsevier Science Ltd. All r ights reserved.