冲压增程炮弹补燃室内铝镁推进剂燃烧流场数值模拟

Numerical Simulation of Al/Mg Propellant Combustion Flow in Secondary Combustion Chamber for Ramjet Assisted Range Projectile

为研究镁对补燃室内燃烧的影响,利用概率密度函数模型和颗粒轨道模型,对冲压增程炮弹补燃室铝镁推进剂的二次燃烧流场进行了三维数值模拟。铝颗粒的燃烧采用蒸发扩散模型进行控制,湍流模型采用标准k-ε两方程模型。考虑镁质量分数、铝颗粒直径的影响,得出了产物组成、温度等发动机参数的变化趋势。结果表明:冲压增程炮弹补燃室头部有两处扩散火焰峰面,然后在补燃室中部混合成为一个火焰;随着镁质量分数由0%增加到15%,铝颗粒的燃烧效率由15%提高至35%;在镁质量分数相同的情况下,随着铝颗粒直径的增大,铝颗粒的燃烧效率减小。

To research the effects of Mg on the combustion in secondary combustion chamber, the Al/ Mg propellant combustion flow in secondary combustion chamber for the ramjet assisted range projectile is three-dimensionally and numerically simulated by using the probability density function （PDF） model and particle trajectory model. Al particle combustion is controlled by a diffusion- vaporization model. The turbulent model is a stand k-ε two-equation model. Considering the effects of Mg mass fraction and A1 particles diameter, the trends of engine parameters such as resultant species and temperature are obtained. The results indicate that two diffusion flame peaks are at the entrance of secondary combustion chamber, and they are mixed into a diffusion flame peak in the middle of secondary combustion chamber. The combustion efficiency of A1 particles increases from 15% to 35% when the Mg mass fraction increases from 0% to 15%. With the same Mg mass fraction, the combustion efficiency of Al particles decreases with the increase of Al particle diameters.