非等温气辅共挤出胀大三维粘弹数值研究

three-dimensional non-isothermal viscoelastic numerical model was established with PTT constitutive equation by the finite element method. The temperature-dependent transport properties were taken into account and were expressed by the Arrhenius equation. The coextrusion processes of LDPE and HDPE was simulated and the velocity field, shear rate distribution and the interface pattern were compared and analyzed. The research results show that the die swell and the interface deflection phenomenon in traditional coextrusion process can be eliminated in gas-assisted coextrusion process. For the gas-assisted coextrusion process, there isn't the secondary flow at the die exit and the flow rate is uniform along the direction of coextrusion, the shear rate distribution is uniform and the value is much smaller than one of conventional coextrusion process.