The effects of magnesium/polytetrafluoroethylene (Mg/PTFE) pyrotechnic compositions on the coupled flow field and reignition mechanism are important aspects governing the performance and range of base bleed projectiles (BBPs). Owing to a decrease in pressure and temperature when the BBP leaves the muzzle, rapid depressurization occurs, which extinguishes the base bleed propellant. The Mg/PTFE pyrotechnic composition pressed in the igniter of the base bleed unit (BBU) provides additional energy to the BBU via a chemical reaction. Thus, the extinguished base bleed propellant is reignited under the effect of high-temperature combustion gas jets from the igniter. In this study, a numerical analysis is conducted to evaluate the effects of PTFE and Mg granularity as well as Mg/PTFE pyrotechnic compositions. Owing to the rapid depressurization, the temperature and pressure was found to decrease for different Mg/PTFE pyrotechnic compositions. However, the depressurization time increased as the PTFE granularity increased, the Mg granularity decreased, and the Mg content increased. When the pressure in the combustion chamber of the BBU decreased to the atmospheric pressure, the combustion gas jets from the igniter expand upstream (rather than downstream). However, these combustion gas jets exhibit different axial and radial expansion characteristics depending on the pyrotechnic compositions used. The results show that the reignition delay time, t_d, of the base bleed propellant was 377.608, 94.27, 387.243, 523.966, and 221.094 ms for cases A–E, respectively. Therefore, it was concluded that the Mg/PTFE pyrotechnic composition of case B was the most beneficial for the reignition of the base bleed propellant, with the earliest addition of energy and mass to the BBP.

镁/聚四氟乙烯 (Mg/PTFE) 烟火组合物对耦合流场和重燃机制的影响是控制基础泄放弹 (BBP) 性能和射程的重要方面。由于 BBP 离开枪口时压力和温度的降低，会发生快速减压，从而熄灭基础排放推进剂。压入基础排气装置 (BBU) 点火器中的 Mg/PTFE 烟火组合物通过化学反应为 BBU 提供额外的能量。因此，熄灭的基础泄放推进剂在来自点火器的高温燃烧气体射流的作用下被重新点燃。在这项研究中，进行数值分析以评估 PTFE 和 Mg 粒度以及 Mg/PTFE 烟火成分的影响。由于快速减压，发现不同的 Mg/PTFE 烟火组合物的温度和压力会降低。但减压时间随着PTFE粒度的增加而增加，Mg粒度减小，Mg含量增加。当 BBU 燃烧室内的压力下降到大气压时，从点火器喷出的燃烧气体会向上游（而不是下游）膨胀。然而，这些燃烧气体射流表现出不同的轴向和径向膨胀特性，这取决于所使用的烟火成分。结果表明，重燃延迟时间，当 BBU 燃烧室内的压力下降到大气压时，从点火器喷出的燃烧气体会向上游（而不是下游）膨胀。然而，这些燃烧气体射流表现出不同的轴向和径向膨胀特性，这取决于所使用的烟火成分。结果表明，重燃延迟时间，当 BBU 燃烧室内的压力下降到大气压时，从点火器喷出的燃烧气体会向上游（而不是下游）膨胀。然而，这些燃烧气体射流表现出不同的轴向和径向膨胀特性，这取决于所使用的烟火成分。结果表明，重燃延迟时间，t _d，对于情况 A-E，基础泄放推进剂的 t 分别为 377.608、94.27、387.243、523.966 和 221.094 ms。因此，得出的结论是，案例 B 的 Mg/PTFE 烟火组合物最有利于基础泄放推进剂的重新点火，并且最早为 BBP 增加了能量和质量。