Simulation of Die Swell and Flow Uniformity of Gun Propellant Dough and Application in Die Design

To analyze the effect law of die structure parameters in extrusion forming process on the swell ratio and flow uniformity of seven-perforation nitroguanidine gun propellant, the extrusion forming process was simulated by computational fluid dynamic method? the primary and secondary relationship of die structure parameter importance was discussed, the die structure for seven-perforation gun propellant was optimized and experimental validation was performed. The results show that the influence of contraction angle of die on the swell ratio and uniformity of dough exit velocity is the biggest, the compression section height is secondary and the forming section length is smallest. The uniformity of velocity distribution at the flow channel exit end after optimization of die is improved by 36. 53% , indicating the reliability and practicability of the simulation calculation.