Abstract
In this work, we examine the shear-banding flow in polymer-like micellar solutions with the generalized Bautista-Manero-Puig (BMP) model. The couplings between flow, structural parameters, and diffusion naturally arise in this model, derived from the extended irreversible thermodynamics (EIT) formalism. Full tensorial expressions derived from the constitutive equations of the model, in addition to the conservation equations, apply for the case of simple shear flow, in which gradients of the parameter representing the structure of the system and concentration vary in the velocity gradient direction. The model predicts shear-banding, concentration gradients, and jumps in the normal stresses across the interface in shear-banding flows.
Highlights
Beyond the local equilibrium hypothesis, the extended irreversible thermodynamics (EIT)provides a consistent methodology to derive constitutive equations for systems far from equilibrium.These equations, together with the conservation laws, predict flow-induced concentration changes produced by inhomogeneous stresses in complex fluids [1,2,3,4].Flow produces changes in the internal structure of complex fluids and induces fluctuations in concentration and in the rheological properties
It is worth mentioning that the inclusion of diffusion in the constitutive equations leads to a finite thickness of the interface between the bands, as shown in the results presented
The model presented here constitutive the equation for the stress, for structural parameter, and for thecontains diffusionthree of mass. They areequations: mutually-coupled by phenomenological the structural parameter, and for the diffusion of mass. They are mutually-coupled by coefficients, and their physical significance arises as they identify with the mechanisms acting on the phenomenological coefficients, andhere their significance they identify withstate, the system
Summary
Beyond the local equilibrium hypothesis, the extended irreversible thermodynamics (EIT)provides a consistent methodology to derive constitutive equations for systems far from equilibrium.These equations, together with the conservation laws, predict flow-induced concentration changes produced by inhomogeneous stresses in complex fluids [1,2,3,4].Flow produces changes in the internal structure of complex fluids and induces fluctuations in concentration and in the rheological properties. Provides a consistent methodology to derive constitutive equations for systems far from equilibrium. These equations, together with the conservation laws, predict flow-induced concentration changes produced by inhomogeneous stresses in complex fluids [1,2,3,4]. Flow produces changes in the internal structure of complex fluids and induces fluctuations in concentration and in the rheological properties. In some analyses of the rheology of these complex fluids, the stress constitutive equation couples with an evolution equation of a scalar representing the flow-induced modifications on the internal structure of the fluid (a variable such as the fluidity or micellar length, in the particular case of giant micellar solutions). An additional coupling of diffusion and structural changes closes this scheme
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