Local studies in horizontal gas–liquid slug flow Original Research Article

The axial liquid-phase velocity profile development in a horizontal air–water plug/slug flow-pattern was experimentally investigated by simultaneously using two hot-film anemometers. One of the probes which was kept in a fixed location was exclusively used as a phase identifier while the other probe was traversed vertically for local velocity measurements. The experimental observations were focused on the intermittent and transient characteristics of the slug flow-pattern. It was shown that the velocity rapidly develops into an asymmetric but nearly fully-developed profile within liquid slug with the maximum value occurring below the pipe center line. On the other hand it was documented that the velocity never develops into a quasi-fully-developed profiles within the liquid layer below a passing slug. At a given location the velocity gradually decelerates toward the gas slug tail, but rapidly accelerates towards the wake of the gas slug.