超声速底部排气弹底部流场与气动特性研究

摘要

In order to study the aerodynamic characteristics of supersonic base bleed projectile,three di-mensional Navier-Stokes equations with chemical reactions are solved using the upwind scheme (AUSMPW+),k-ω SST turbulence model,8 species and 12 reaction kinetics model,and second-order turbulent com-bustion model.The reliability of the numerical methods have been validated firstly,then the real base bleed gas flow field of the supersonic base bleed projectile are numerically simulated.The rule of the effect of the attack angle and boattail angle on flow structures,together with aerodynamic characteristics are analyzed. Calculation results show that:attack angle has a certain influence on the flow structures.With the increases of attack angle,the area of the initial recirculation zone in both the windward and the leeward side increase, and the initial recirculation zone in the windward is always less than that in the leeward side;with the in-crease of attack angle,the aerodynamic coefficient,such as base drag coefficient and total drag coefficient, would increase;there has a best boattail angle under different conditions.The change of the boattail angle will change the flow structure in the base flow,and affect both the region and the strength of the secondary combustion of rich-fuel gas.The study results can provide a reference for the further study on drag reduction using base bleed and the design of base bleed projectile.%为了研究超声速底部排气弹气动特性，采用 AUSMPW＋迎风格式、k-ω SST 湍流模型、8组分12反应化学动力学模型和二阶矩湍流燃烧模型耦合求解三维带化学反应的 Navier-Stokes 方程。在数值方法的有效性和可靠性得到验证的基础上，对超声速底部排气弹底排真实气体流场进行了数值模拟，分析了攻角和船尾角对底部排气弹的底部流场结构和气动特性的影响规律。计算结果表明：攻角对底部流场结构影响较大。随着攻角的增大，迎风面和背风面的初始回流区体积逐渐减小，且迎风面的初始回流区体积始终小于背风区；随着攻角的增大，底部阻力系数、总阻力系数等气动系数均增大；不同工况下存在着相应的最佳船尾角。船尾角的改变会引起底部流场结构的变化，同时影响着富燃气体的二次燃烧区域与强度。有底部排气时对应的最佳船尾角比无底部排气时的最佳船尾角小。