Extrusion Swelling on the Co-Extrusion Process of Variable-Burning Rate Propellant by Numerical Simulation

The three-dimensional flow of seven holes variable-burning rate propellant in co-extrusion dies was simulated based on finite element method. The influence of long diameter ratio to interface radius and extrusion swell were analyzed. The result shows that keep the length to diameter ratio L/D0 between 3.5 ~ 13, can control interface radius changes in the process of the extrusion processing co-extrusion processing .And D/D0 reflect the viscoelastic fluid from the shear strain response ability.