面向再入飞行器概念设计,提出了一种实现外形多目标优化的综合设计方法。基于类型函数/形状函数变换技术建立参数化几何模型,实现了以少量设计变量描述较大范围的设计空间;引入考虑真实气体效应的工程方法估算气动特性,应用非支配排序遗传算法(NSGA-Ⅱ)实现考虑升阻比和容积利用率最大化以及热流量最小化的多目标优化设计;通过减法聚类提取典型设计构型,并根据分层图可视化地从Pareto前端与Pareto最优解集中定量筛选设计方案。双锥布局再入飞行器优化结果表明,可以在不损失容积利用率的情况下,使设计点处配平升阻比从0.65提高到0.94。该方法同时还有利于概念设计中有效压缩设计空间和确定外形设计参数选择的方向与范围。
This paper presents a multi-objective shape optimization method for the conceptual design of reentry vehicles. The class function/shape function transformation technique is used to represent briefly the various shapes of the reentry vehicles with relatively few variables. The aerodynamic characteristics of the vehicles are predicted by an engineering method which accounts for the effects of real-gas flow across the oblique shock wave. The multi-objective evolutionary algorithm non-dominated sorting genetic algorithm (NSGA-Ⅱ) which produces a set of Pareto solutions is employed as the optimization strategy to trade off the maximization of lift-drag ratio, volumetric efficiency, and the minimization of overall heat rate. Representative configurations are then obtained using a subtractive clustering algorithm and an optimum solution is visually identified with level diagrams which is a graphical rephical representation of the Pareto front and set. Design optimization of a bicone baseline configuration demonstrates that the trimmed lift-drag ratio is improved from 0.65 through 0.94 without reducing volumetric efficiency. This method also contributes a great deal to the reduction of the design space of a conceptual design and the determination of aerodynamic shape parameters.
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