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.

Numerical Simulation on the Whole Co-Extrusion Process of Tread Rubber

The Phan-Thinen and Tanner (PTT) model was used to describe the co-extrusion behavior of tread rubber which is made up of two components. To investigate the effects of upper and lower channels on simulation results, two kinds of Finite Element (FE) models were established. One of them contained the upper and lower channels, while another did not. Comparison between the computational results and corresponding test data illustrates that the difference of these two models is obvious, which suggests that the consideration of upper and lower channels play an important role in analysis on polymer’s co-extrusion process. Besides, we also analyzed the effects of wall slip coefficients on co-extrusion products. The results show that the decreasing of wall slip coefficients can reduce the extrusion swell phenomenon effectively, but it may bring out the distorting of the corner parts of co-extrusion section shape. Therefore, various factors need to be comprehensive taken into account in the selection of wall slip coefficients.

Study on the Composite Spinning Co-Extrusion Process of the Tri-Component

In the molding process of the tri-component composite spinning, the flow control of each component plays a significant impact on extrusion swell. This paper simulates the extrusion swell of the tri-component fiber in different flow ratio of different components based on Polyflow fluid dynamics simulation software, and measures the extrusion swell ratio of the tri-component fiber in different flow ratio of different components through the experiment. Simulation and experimental results show that by adjusting the melt flow ratio of the various components, we can obtain the desired extrusion swell ratio, which can improve the performance of the tri-component fiber.