The experiments aimed to determine the flow transition are
carried out in the SMX10 and in the SMX+6, with a reference method
to avoid any hysteresis effect. For a given value of the liquid
flow-rate in the range [8–50] L/h, the gas flow-rate is decreased
monotonically starting from the maximum value, where the slug
flow is generally observed. The tested range of gas flow-rate is
[0.02–0.45] Nm3/h. Once the gas plugs disappear, the corresponding
gas flow-rate is recorded as well as pressure drop and gas injection
pressure. Limits between the regimes are visually determined
at the outlet of the static mixers.