Flow Behavior of Thixoplastic Semisolid Alloy Slurry in a Channel Coated by Poroelastic Lining

Pressure-driven laminar flow of a thixo-viscoplastic semi-solid slurry obeying Houska model is theoretically investigated under steady (fully-developed) condition in a two-dimensional channel coated by a thick poroelastic lining. Treating the poroelastic layer as a two-phase solid/liquid material, bi-phasic mixture theory is used to determine the velocity of the Newtonian fluid (e.g., air) trapped in the pores of this linearly-elastic layer. The main objective of the work is to investigate the effect of semi-solid’s properties (viscosity ratio, decay ratio, and yield stress) on the velocity profile and/or flow rate for a given pressure gradient. We are as well interested in the effect of porosity and permeability of the layer for given elastic modulus on the velocity profile of the slurry. A highly nonlinear ODE is derived for the velocity gradient which is solved numerically using finite-difference method subject to appropriate interfacial boundary conditions. The results show that an increase in the ratio of zero-shear-viscosity to infinite-shear-viscosity has a retarding effect on the flow. On the other hand, an increase in the decay parameter (which means a weakening of thixotropic effect) has an accelerating effect on the flow. As expected, an increase in zero-shear yield stress also has a retarding effect on the flow. In cases where it is not possible to have any control on the thixo-viscoplastic behavior of the semi-solid slurry, it is suggested that the flow rate can be increased using more porous and/or more permeable layers.

Keywords:

Semisolid , Thixotropic , Quemada model