Numerical simulation of three dimensional flow field for extrusion process of GR-35 double-base propellant

Due to the instability of materials and the screw's rotation friction, it will be dangerous in the screw extrusion process of solid propellant. Because there were so much nitroglycerin and solid part in GR-35 double-base propellant, it was more difficult in spiral extrusion for this important propellant than others. In order to solve this problem, the Polyflow software was used to simulate the spiral extrusion process of GR-35 in this paper. Then four parameters (the temperature, the pressure, the shearing rate and the velocity) were analyzed at the axial direction (Z=0.02 m and Z=0.08 m). Then, these parameters of Z direction were analyzed by a line near the arris. According to the results, no matter the value of temperature, pressure, shearing rate or velocity, was larger in screw arris position. In addition, the values of temperature and pressure will increase as the extrusion processes while the velocity and the shearing rate will decrease. The simulated results can be used to optimize the technological in the process of screw extrusion of solid propellant and decrease the risks in process. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).