STRATIFICATION IN ISOTHERMAL ICE-SLURRY PIPE FLOW

A single-phase 3D model for isothermal laminar and turbulent flow of an ice slurry in a horizontal pipe is used to investigate the effects of the uniform inlet velocity and ice concentration on their axial evolution. The slurry is modeled as a Newtonian fluid with effective local properties depending on the local ice concentration. Despite the relative simplicity of this model (compared to the two-phase models used elsewhere) its numerical solution gives results which correctly reflect experimental observations. Specifically, these results show that as the fluid moves downstream the ice concentration increases in the upper part of the pipe and it decreases in the lower part. The velocity profile is principally influenced by the boundary layer growth close to the inlet but further downstream it becomes asymmetrical with respect to the horizontal symmetry plane with higher velocities in the lower part of the pipe. The differences between the values in the upper and lower parts of the pipe are much more important in the case of laminar flow. The results are analyzed by considering the phenomena influencing the ice particle movement (buoyancy and diffusion) and the relation between ice concentration and the thermophysical properties of the slurry.