Plane flow of thixotropic elasto-viscoplastic materials through a 1:4 sudden expansion

Non-Newtonian Two-Phase Flow Characteristics across Sudden Expansion in Horizontal Rectangular Minichannel

“…This is due to the highest viscosity among the three test liquids, causing thicker liquid film between the bubble slugs and the channel wall, and reducing the flow area of the bubbles. Figure 8 shows a comparison of bubble velocity between experiment and calculation by the drift flux model of Zuber and Findlay [22], Equation (5), together with Equations (7) and (8). The calculations agree with the data within root mean square errors of 20%.…”

“…The cyclohexane was used as the dispersed phase, and various concentrations of Carboxymethyl Cellulose (CMC) aqueous solutions as the continuous phase. Link et al [8] realized a numerical investigation of an elasto-viscoplastic thixotropic fluid flowing through a 1:4 plane expansion using a recently proposed constitutive equation. The conservation equations were solved using a four-field Galerkin least-squares formulation in terms of the extra stress, pressure, velocity, and structure parameter, i.e., a scalar quantity that represents the structuring level of the material microstructure.…”

Transient motions of elasto-viscoplastic thixotropic materials subjected to an imposed stress field and to stress-based free-surface boundary conditions

“…Two kinds of boundary conditions were imposed at the top: constant velocity and constant force. Among the few examples of numerical works on elasto-viscoplastic thixotropic materials are the works of Fonseca, Frey, Naccache, and de Souza Mendes (2013) , where a Maxwell based viscoelastic model is used as a basis for the inclusion of viscoplastic and thixotropic effects and ( Link, Frey, Thompson, Naccache, & de Souza Mendes, 2015;López-Aguilar et al, 2015 ) where an Oldroyd-B based viscoelastic model is the original backbone.…”

“…This implies that the second invariant of the deviatoric part of the stress must overcome the yield stress obtained in shear, here called τ y 1 , in order to trigger the breaking of the microstructure. In this sense, the attractor point of the current non-equilibrium state, among all points that belong to the flow curve, is the point corresponding to the current value of the square root of the second invariant of the deviatoric part of the stress ( Link et al, 2015 ). In this sense, we can say that the relation between λ eq and the stress tensor reduces to…”

Shear-induced particle migration in the flow of particle suspensions through a sudden plane expansion

“…Numerical simulations of non-Newtonian fluids flowing through abrupt expansions have been presented by different researchers. For instance, these works considered the cases of power-law fluids [39][40][41][42], viscoelastic fluids described by classical constitutive differential equations [43][44][45][46][47][48], yield-stress liquids with and without elastic effects [49][50][51][52][53], and thixotropic materials [54]. The particular case of suspensions of particles flowing through sudden expansions and bifurcations has important applications in manufacturing and biological processes, such as in blood cell separation methods [55][56][57].…”