Effects of Mg/PTFE pyrotechnic compositions on reignition characteristics of base bleed propellants and heating mechanism  

作　　者：Xiao-chun Xue Long-ze Ma Yong-gang Yu 

机构地区：[1]Schooi of Enerey and Power Engineering Nanjing Universiry of Science and Techmology Narine lianesu,210094 China [2]BYD Compary Liruied ShenzheL Guanedong 518118 Chna

出　　处：《Defence Technology（防务技术）》2022年第1期94-108,共15页Defence Technology

基　　金：This work was supported by the Fundamental Research Funds for the Central Universities(No.30918011324).

摘　　要：The effects of magnesium/polytetrafluoroethylene(Mg/PTFE)pyrotechnic compositions on the coupled flow field and reignition mechanism are important aspects governing the perfommance 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 py-rotechnic 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 compo-sitions.Owing to the rapid depressurization,the temperature and pressure was found to decrease fordifferent Mg/PIFE 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,ta,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.

关 键 词：Thermal effect High-temperature combustion gas Mg/PTFE pyrotechnic Compositions REIGNITION 

分 类 号：TJ201[兵器科学与技术—武器系统与运用工程]