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针对返回舱再入过程中需要满足的复杂气动力热条件,在典型高超声速条件下以升阻比和阻力系数为目标,以驻点热流和容积率为约束条件进行返回舱外形多目标优化设计。气动特性分析采用基于三维Navier-Stokes方程和结构网格的计算流体力学数值仿真(CFD)方法,采用Fay-Riddell经验公式计算驻点热流,采用NSGA-II优化算法进行全局寻优,为了增强多目标优化设计的计算效率,利用Kriging代理模型替代CFD计算,并引入改进的EI函数加点策略,大大减少了构建代理模型时所需的样本点数目。优化计算结果表明,代理模型计算结果与CFD计算结果误差可以控制在7%以内,基于代理模型技术的优化过程可以节省95%以上的计算开销。因此,该方法能够较好地满足初步设计的要求,为返回舱外形优化提供有益的借鉴。
Aiming at the complex aerodynamic heat conditions to be met during the reentry of the return capsule, the lift-drag ratio and resistance coefficient are set as the targets under the typical hypersonic conditions, and the multi-objective optimization of the shape of the return capsule is carried out with the stagnation heat flux and volume ratio as the constraints . Aerodynamic Analysis CFD method based on three-dimensional Navier-Stokes equations and structural grid is used to calculate the stagnation heat flux by using Fay-Riddell empirical formula and global optimization by NSGA-II optimization algorithm. In order to enhance The computational efficiency of goal optimization design, Kriging proxy model instead of CFD computing, and the introduction of improved EI function plus strategy, greatly reducing the number of sample points required to build the proxy model. The results of optimization show that the error between the calculated result of the proxy model and the CFD calculation result can be controlled within 7%, and the optimization process based on the proxy model technology can save more than 95% of the computational cost. Therefore, this method can better meet the requirements of the preliminary design, and provide a useful reference for the optimization of the shape of the return capsule.