Thermally Induced Flow Front Instabilities in Injection Moulding

The temperature distribution of a polymer melt, injected between two, cooled, plates is calculated. For this, the two-dimensional region occupied by the melt is divided into a part (G I ) far behind the flow front and a part (G II ) near the flow front. The melt is modelled as a Newtonian fluid. The temperature is governed by a diffusion-convection equation with appropriate boundary conditions. Asymptotic expansions, based on the small value of the dimensionless thermal conductivity are used. Both in G I and G II , boundary layers exist near the cooled walls.