7. Numerical simulation of the rotational molding process

7.1 Flow of the reactant mixture

The simulation of reactive rotational molding when the initial mixture is in the liquid state (pre-gel phase) requires accounting of fluid flow, of heat transfer and of the polymerization reactions. The fluid is considered as an incompressible viscous Newtonian fluid whose viscosity, at each temperature, is a function of the advancement of the polymerization reaction (conversion rate) ; moreover, the shear rate is negligible because the rotation speed is low (1 to 10 rpm). The result of interest is the displacement of the free surface as a function of time which is governed by the competition of two main forces, gravity and viscosity. The simulation is carried out using the SPH (Smoothed Particle Hydrodynamics) method which is very suitable for...