FLOW STRUCTURE IN THE HORIZONTAL SLUG FLOW

Abstract

Successions of long gas bubbles and liquid slugs form the so-called slug flow
pattern in a gas-liquid flow. A unit cell encompassing one gas bubble and one
liquid slug characterizes this alternating gas-liquid flow. The kinematic and
dynamic flow mechanisms responsible for the interactions between the successive
unit cells are still an open question. Inside this context, this work addresses
specifically to the bubble velocity, the bubble to bubble interactions and the
entrance mechanisms. Within an experimental framework the spatial evolution of
each unit cell structure is individualized during the acquisition period. The
experimental apparatus consisted of a 23.4 m long transparent Plexiglas pipe,
26mm ID, which means a total relative length of 900 free diameters. The air and
water were mixed at the inlet of the test section and discharged into a collecting
tank open to the atmosphere. The instantaneous measurements of the flow structure
were made with double-wire conductive probes. The probes were installed in
four measuring stations; each station had two probes slightly apart. The measuring
stations were located at 127D, 273D, 506D e 777D from the mixer. The
experimental database is further processed to give rise to histograms and
correlations among flow variables