Simulation and Experimental Study with Structural Parameter Optimization on Gun Propellant Single-screw Extruder

Single-screw extruders are widely used in gun propellant production. The outlet diameter (do) of the extruder and screw rotational speed (n) are important factors affecting process safety. To improve the operational safety of the single-screw extruder, a targeted study on internal pressure (P) during the extrusion process was performed. First, using the computational fluid dynamics (CFD) software Ansys Polyflow, a model of the non-isothermal non-Newtonian fluid inside the single-screw extruder was established. Then, using data collected from an experimental single-screw extrusion device, the simulation results were verified and analyzed. Simulations and experiments showed that when do is small and n is accelerated, the slope and fluctuation of P increase significantly, and the extrusion state gradually becomes unstable. When do is large, the increase in P is restricted due to the relief effect. To further investigate the influence of screw structure on safety and stability, orthogonal optimization was adopted to simulate the influence of pitch (ps), screw edge width (ws), and screw groove depth (ds) on the maximum pressure value (Pm) and maximum pressure difference (Pd). Additionally, the influence of ps on P was studied using the single factor method. The results showed that the maximum Pd under the optimal combination of structural parameters obtained by the orthogonal optimization had increased by ۶.۰۵% compared with that before optimization. ps had the greatest influence on the pressure value while an increase in ps caused the maximum Pd to increase and then decrease. This study established the influencing factors and variation patterns of pressure during extrusion, offering engineering guidance for the safe production of gun propellant.

کلیدواژه ها:

Extrusion process ، Experimental verification ، Numerical simulation ، Structural parameter optimization