In this study, we propose to investigate the effect of the flow
conditions and of the liquid base properties in two SMX static mixers
characterized by different hydraulic diameters. The experiments
are designed to determine the flow process conditions in
SMX static mixers enabling formation of foams at lower void fractions.
Firstly, a hydrodynamic study is performed through the
determination of the respective characteristic constants: Kp, the
power constant, and Ks, the shear rate constant evaluated by the
Metzner–Otto method (Metzner and Otto, 1957). The hydrodynamic
conditions allowing complete and homogeneous gas incorporation
and corresponding to the bubble regime are
experimentally determined, by varying the gas and liquid flowrates
for each tested solution. Foams are made of whey protein isolates
(WPI) as foaming agent and xanthan gum (XG) at different
concentrations to modulate the liquid viscosities, elucidating the
effect of liquid base viscosities on the flow pattern