Abstract: the distribution of pressure and velocity in the pressure drop die for microcellular polymer extrusion was simulated using FLUENT software with the structures and boundary conditions simplified.It was found that the pressure drop decreased with increasing melt temperature and CO2 concentration and increased with increasing melt flux. the velocity distribution in the vessel was uniform, but increased suddenly at the entrance of capillary. Pressure drop and velocity was influenced greatly by melt flow and CO2 concentration and only moderately by temperature.

Key words: microcellular plastics, extrusion, numerical simulation, pressure drop, die