MT烟火药高压稳态燃烧射流场的数值模拟

Numerical Simulation of Steady MT Combustion Jet Flow Field Under High Pressure

为研究镁-特氟隆(MT)基烟火药在不同工况下的燃烧过程,建立了MT烟火药柱二维稳态燃烧流动模型,气相反应采用简化的三步反应动力学机理,利用CFD软件Fluent,数值分析了MT稳定燃烧时的射流形态及流场参数分布特性。结果表明:燃烧流场温度在燃面上方50 mm内处于急剧上升阶段,也是气相反应区域;镁的质量分数为0.45~0.61时,其含量越小,温度越高,且越靠近火焰核心,温度梯度越大;压力为0.1~5 MPa时,随着压力升高,火焰核心向下游移动,动力学反应速率明显增大,CF_2组分分布核心和Mg的氧化还原反应核心向下游移动,而C组分分布核心和C-C结合反应核心由一个中心区逐步分裂移至两侧,形成两个小的核心区。

A two dimensional steady-state CFD combustion model is developed to investigate the combustion progress of Mg-Teflon （MT） pyrolant in different burning situation. A simplified gas-phase chemical kinetic mechanism with 3 reactions has been used to study the shape of jet flow field and parameters distribution characteristics of the steady MT combustion with CFD software Fluent. Results show that the flame temperature increases sharply above the burning surface about 50 mm, where the reactions occur. The less the mass fraction of Mg （0.45~0.61） is, the higher the temperature is. And the closer the place is, the larger the temperature gradient is. The pressure changes from 0.1 MPa to 5 MPa, which results in the flame center moving towards downstream and obviously increasing kinetic rate of reaction. Both of the CF2 distribution center and the oxidation- reduction reaction center of Mg move towards downstream. The distribution center of carbon and C-C recombination reaction center are split to double smaller centers on both sides of the reaction zone.