1993 Volume 7 Issue 3 Pages 250-261
A two-phase flow experiment was conducted using a 200mm diameter, 100m long straight pipe with adjustable gradient. A steel pipe with transparent plastic parts was used. Superficial water and air velocities were from 0 to 1.5m/s and 0 to 10m/s. Pipe gradients were horizontal, 0.2%up, 0.8%up and 0.5%down. Test results were as follows, 1. 0bserved flow pattern in horizontal and inclined pipe was almost the same as that of the preceding 300mm pipe experiment. Flow pattern is extremely sensitive to pipe gradient. 2. Intermittent flow pressure loss was relatively low by comparison with that reported in the literature on the matter. Its pressure loss was between the mixed flow model pressure loss and the separated flow model pressure loss. An empirical formula of pressure loss was obtained. 3. Void fraction of intermittent flow was also relatively low compared with other reports. It was concluded that low up-gradient did not affect the void fraction but down-gradient did. An empirical formula of void fraction was obtained. 4. Up-gradient flow showed an air lift effect which was consistent with the void fraction.
