环形腔对燃气弹射初容室二次燃烧影响数值研究

为了研究环形腔对燃气弹射初容室内二次燃烧的影响，采用RNG k-ε湍流模型、有限速率/涡耗散燃烧模型和域动分层动网格技术，建立了考虑导弹尾罩运动的初容室二次燃烧流动模型。在与无环形腔弹射装置实验数据对比验证的基础上，数值研究了有/无环形腔和环形腔不同开口方向初容室流场、弹射内弹道和载荷变化规律，分析了环形腔降低二次燃烧冲击的机理。结果表明：从流场结构来看，增加环形腔结构改变了燃气流扩散方向，减小了燃气与空气的接触面积；含有环形腔流场增加的回流区域降低了尾罩底部二次燃烧产生的压强峰值。从内弹道角度来看，与无环形腔相比，环形腔开口向上时，导弹加速度变化平缓，出筒速度减小5.9%，出筒时间推迟4.5%.

The Influence of Annular Cavity on Secondary Combustion of Gas-ejection Initial Cavity

To study the influence of annular cavity of gas-ejection launcher on secondary combustion, RNG k-ε turbulence model, finite-rate/dissipation model and dynamic mesh update method are adopted to establish a secondary combustion model of initial cavity, in which the movement of rear cover is considered. Compared with experimental result of ejection launcher without annular cavity, the variation in fluid structure, ejection interior ballistics and variation in load are studied for the initial cavity with/without annular cavity and the initial cavity with different opening directions. The mechanism of that annular cavity reduces the secondary combustion impact is analyzed. Results show that, from the point view of fluid structure, an annular cavity can is added to change the direction of gas diffusion and decrease the area between gas and air. The backflow region with annular cavity can decrease the pressure peak caused by secondary combustion. From the point view of interior ballistics, the acceleration of missile in which the annular cavity opening is formed upwardly changes gently, the velocity out of tube is reduced by 5.9%, and the time out of tube is delayed by 4.5%.