Flow Structure when Filling a Channel with a Curable Liquid

The filling of a plane gap with a non-Newtonian fluid under non-isothermal conditions is considered by assuming viscous dissipation and curing reaction induced by the heat supplied through the walls of the gap. The rheology of the medium is described by the modified Cross-WLF model accounting for the effect of temperature, strain rate intensity, and the extent of a chemical reaction on the viscosity. The curing reaction kinetics is determined by the equation based on the n-th order reaction with self-acceleration. The problem is solved numerically using an original computational technique. The curable fluid flow structure is revealed to include three characteristic zones during the filling process: a fixed layer on the solid wall with a high degree of curing; a central “core” with an almost uniform distribution of characteristics; and a transition zone serving as a "lubricating" layer between two abovementioned zones. The structure is governed by heating of the fluid through the wall, since the heating affects the rheological characteristics of the medium and the rate of the cured layer formation. Analysis of the similarity criteria for the considered flow conditions shows that the fluid flows in a creeping regime (Re < ۰.۰۱); the temperature distribution is mainly affected by convective heat transfer (Pe > ۱۰۰); the influence of dissipative heating and exothermic effect of the curing reaction is insignificant. The effect of curing on the mass distribution of the liquid portions entering through the inlet section is shown. The variation of the pressure distribution is analyzed at various flow conditions.

Keywords:

Non-Newtonian fluid , non-isothermal , Curing , free surface , Numerical simulation