The flow pattern map coordinates (Us,l, Us,g) presented in Fig. 6,
are established from eight flow-rates pairs (Ql, Qg) and for three liquid
solutions. In the present study, the plotted frontier corresponds
to the transition between the two flow regimes observed
within the experimental range, which are the ‘‘dispersed’’ regime
that allows a complete incorporation of the gas, and the so called
‘‘slug flow’’ regime that occurs at high gas flow-rates. Other types
of existing flow patterns (plug, annular, stratified, etc.) are not observed
over the present range of conditions. Theoretical foam void
fractions are mentioned on the maps by contours of iso-values;
they are straightforwardly deduced of the flow-rates, but of course
the validity is limited to the bubble regime area. Some representative
experimental values taken at the frontiers are gathered in
Table 5.