Evaluating the Foaming Behavior of High-Viscosity Non-Newtonian Fluids

Here, a dimensionless empirical parameter is proposed to comprehensively evaluate the foaming properties of high-viscosity non-Newtonian surfactant fluids. Rheological measurements were used to probe the viscosity, viscoelasticity, and viscous flow activation energies of the materials. Additionally, an advanced Focused Beam Reflectance Measurement (FBRM) online characterization technique, in conjunction with traditional microscopic observations, was used to quantitatively examine the generation, distribution, and destabilization of bubbles during the foaming process. This is the first time that the FBRM technique has been used for online quantitative analysis of bubble distribution. Three dimensionless parameters were proposed to describe the foaming properties of the fluids, namely the volume fraction of gas, Φ, the coefficient of dispersion of the bubble size distribution, c, and the fraction of span change for 10 min, Δs. These properties represent the foam generativity, dispersibility, and stability, respectively. A dimensionless parameter, the foaming property index (FPI), is proposed to provide an overall evaluation of the foaming behavior based on the intrinsic properties of the fluid. Finally, the results of foaming experiments under the same mixing conditions demonstrated that the index provides a simple and reliable estimate of foaming performance, which is expected to aid in the industrial design of foaming unit operations for non-Newtonian fluids.