Irreversible thermodynamic theory of shear-induced melting point depression

Abstract

Extended irreversible thermodynamics is applied in this paper to study the effect of shear on two-phase equilibrium between a liquid and its solid. The theory predicts a lowering of the melting point of the solid when the liquid is sheared in a plane Couette flow geometry, regardless of whether the liquid is Newtonian or non-Newtonian. A model is used for the temperature dependence of viscosity to estimate the melting point depression which increases with the shear rate. In the case of an activation energy for viscosity sufficiently low compared with the thermal energy the melting point depression is proportional to the square of the Reynolds number. Although for a system different from the experimental ones, this Reynolds number dependence is reminiscent of that observed by Goldburg et al. on critical binary mixtures subjected to a random (turbulent) stirring.