Development of Co-Extrusion Technologies for Green Manufacture of Energetics

摘要

The manufacturing of co-extruded grains of highly filled propellant suspensions is a complicated operation, which requires a detailed and realistic understanding of the various types of interface, surface, and bulk instabilities. This understanding is necessary to be able to successfully manufacture fast core propellants using co-extrusion (ram or twin screw extrusion based). In this investigation, the fundamentals of the co-extrusion process were investigated by a combination of experimental and simulation studies. The project included the development of a novel experimental apparatus, which was used to investigate various type of flow instabilities and to collect basic data on various aspects of the fundamentals of the co-extrusion process. Furthermore, an analytical model of the process was developed by Prof. Kalyon to allow determination of the pressure drop versus flow rate relationships along with the velocity and shear stress distributions when two fluids are co- extruded side by side. The viscoplasticity and the wall slip of the two suspensions could be accommodated. The agreement between the theory and the experimental results was acceptable. In this final report, the techniques and the results obtained are outlined along with a listing of the reports and presentations that were made and a list of lessons learned.