基于近似模型的空心弹气动外形数值优化

Numerical optimization of aerodynamic configuration of a hollow projectile based on the approximation model

作为一种新型超声速弹药,空心弹具有阻力小、精度高等优点,在航空与防空弹药领域具有广阔的发展前景。本文以课题组前期研究的某30mm空心弹为例,基于四阶多项式响应面近似模型,综合运用UG、ICEM CFD、FLUENT、MATLAB等软件,结合单纯形法,以最小阻力系数为目标对空心弹的气动外形进行了优化,得到了α=0°、Ma=3.0条件下的空心弹最小阻力系数及气动外形参数,该阻力系数与前期数值模拟研究结果相同。在此基础上,以最小阻力系数为目标对α=0°与4°、Ma=2.5~4.0条件下的气动外形进行了优化,得到了相应外形参数的变化范围。另外,利用Kriging近似模型和NSGA-Ⅱ优化算法等,并以最小阻力系数和最大升阻比为目标,对α=4°、Ma=3.0条件下的空心弹气动外形进行了优化,得到了相应的优化外形。与初始弹形相比,优化后空心弹的气动阻力明显减小。本文验证了近似模型可用于空心弹气动外形优化设计,可为相关工程应用与研究提供重要参考。

As a new type of supersonic ammunition, the hollow projectile hasadvantages of low drag and high precision etc. , and it has wide applications in aircraft and air defense field. In this paper, based on fourth-order polynomial response surface approximation model, combined with the application of UG, ICEM CFD, FLUENT, MATLAB, etc. , and simplex method, the aerodynamic configuration of our previously studied 30mm hollow projectile has been numerically optimized for minimum drag coefficient, and the minimum drag coefficient and optimal aerodynamic configuration parameters were obtained for the hollow projectile at angle of attack α=0° and Mach number Ma = 3.0. The minimum drag coefficient has good agreement with our previous numerical result. Based on the same optimal object of minimum drag coefficient, the aerodynamic configuration has been optimized at α=0°, 4°, and Ma=2.5～4.0, and the variation ranges of corresponding configuration parameters were obtained. Moreover, by using Kriging approximation model and NSGA-II optimization algorithm etc. , based on optimal objects of minimum drag coefficient and maximum lift-drag ratio, the aerodynamic configuration of the hollow projectile has been optimized numerically at α=4° and Ma = 3.0, and the optimal aerodynamic configuration has been obtained. Compared with the original hollow projectile, the aerodynamic drag force of the optimized one is significantly reduced. It is verified that approximation model can be applied to optimize aerodynamic configuration of a hollow projectile. This study can provide important guidance for relative engineering applications and investigations.