Topic: Co-Current gas-liquid flow in slightly inclined pipes
Presented by: John Lioumbas, Ph.D. Chemical Engineering, Thessaloniki, Greece.
The co-current stratified gas–liquid flow is a flow regime frequently encountered in
long distance hydrocarbon pipelines, as well as in transfer lines in process plants.
The accurate characterization of both the structure of the gas–liquid interface and of
the flow field inside the liquid layer are considered essential to understand the
mechanisms involved in the evolution of waves at the transition from smooth to wavy
stratified flow regime. Moreover, the presence of small amounts of additives in
flowing liquids largely affects a wide range of phenomena (e.g. stability of laminar
flow, transition to turbulence). More specifically, the pressure drop reduction
phenomenon, associated with this addition and manifested as drag reduction,
significantly lowers energy consumption in turbulent single-phase flow in pipes.
In this study the following topics are presented:

Experimental examination of the Interfacial characteristics and the liquid
velocity profile during free falling film and co-current gas-liquid flow in slightly
downward inclined pipes.

Surfactants, Drag reduction and Gas-Liquid interface modification in slightly
inclined pipes.
The scope of this work is twofold: First, to study the transition from smooth to wavy
stratified flow for various pipe inclination angles and gas–liquid flow rates. Secondly,
to study the effect of surfactant addition on the transition from smooth to wavy
stratified flow in inclined pipes for a range of pipe inclination angles.
The study of the liquid flow field structure, through local axial velocity measurements,
in conjunction with the liquid layer characterization experiments is aimed at
elucidating the influence of the liquid flow field on the interfacial structure.