CFD Characterization of a Wet Foam Flow Rheological Behavior

Abstract

In some industrial processes, aqueous foams flow presents an important phase of the process, whereas, they cause pressure drop when designing and dimensioning systems. Identifying the different rheological parameters of foam flow is an interest key to understanding the interfacial phenomena. Actually, the difficulty to model the rheological parameters of foam flow is a major challenge. In this study, we present a robust model to describe the foam fluid inside horizontal channels by the reverse approach of a numerical simulation (Computational Fluid Dynamics: CFD), based on the behavior laws of the Herschel-Bulkley type, for the non-Newtonian fluids. This reverse method starts from experimental (deduced from Particle Image Velocimetry (PIV) technique) results of the previous experimental work of Chovet (2015). The pressure losses measurements near-wall velocity fields, velocity profiles and the wall shear stress evolution including the void fraction from 55% to 85%, are considered in order to identify the different parameters of the developed model to determine the nature of the flow, the foams rheological behavior and the foam flow regime along the length of the channel. The numerical study (CFD) is applied for two conditions: the first one for a wet foam flow with a void fraction of 70% and a foam flow velocity of 2cm/s (one-dimensional regime) and the second one, for a foam quality of 55% and a flow rate of 6cm/s. The numerical evolutions are identical to experimental ones for these same conditions. Therefore, we can conclude that the Herschel-Bulkley rheological model can correctly describe the aqueous foams fix behavior.

Gas and Liquid Phase Imaging of Foam Flow Using Pure Phase Encode Magnetic Resonance Imaging

“…This model has previously been used to describe the flow of aqueous foams. A foam quality value (defined as the ratio of the volume of the gas in the foam to the total liquid and gas volume of the foam) of 0.75 was used for the simulations, based on parameters provided in [17]. A foam quality factor below 0.52 represents a foam that consists of spherical bubbles that are not in contact with each other.…”

“…This paper demonstrates the use of motion-sensitized SPRITE MRI as a measurement technique for the study of foam flow and the comparison between gas and liquid phase velocity maps. Further, this paper presents the use of the Herschel-Bulkley viscosity model as a means of modelling the foam flow through the pipe, rather than more computationally intensive methods [17,18]. Computational fluid dynamics (CFD) simulation results created using this model are presented and found to be only superficially similar to experimental results, suggesting the future use of MRI measurements to guide CFD simulations of foam behavior.…”