高超声速滑翔式升力体外形设计与优化

针对高超声速飞行器外形参数多、气动布局设计复杂的问题,基于类型函数/形状函数变换技术和幂函数表达方法,采用6个控制参数设计了一种便于分析与设计的升力体构型。通过正交试验分析了各参数对升力体容积率和升阻比的影响,得到了对性能影响较大的参数,并发现几乎所有的控制参数对容积率和升阻比的影响趋势都是相反的,进而以纵向稳定性和容积为约束条件,对升阻比和容积率进行多目标优化。结果表明,基于Kriging代理模型技术的多目标优化方法计算效率高,得到的优化前缘均匀,典型优化结果的容积率和升阻比较基本外形分别提高17.31%和11.94%,并且由于代理模型构建时采用了改进的EI加点策略,优化结果的误差能达到4%以内,完全满足初步设计的要求。另外研究了边缘钝化对优化设计结果的影响,边缘钝化能显著减小升阻比,钝化半径越大升阻比越小。而且当仅考虑气动力特性时,基于尖锐前缘外形得到的优化结果能直接外推到钝化条件下。

Configuration optimization design of hypersonic gliding lifting body

The large number of configuration parameters of the hypersonic vehicle makes its aerodynamic shape design very complicated. To overcome this difficulty, a lifting body shape parametric design method is proposed. This method is based on class function/shape function transformation (CST) and power function expression, whose design variables are limited to six and which makes it very convenient for configuration analysis and design. By means of orthogonal experiment analysis, influence of the configuration parameters on volume efficiency and lift-drag ratio of the lifting body is studied, the ones with the great influence are obtained. Meanwhile, the experiment results found that the configuration parameters have conflict influence on the volume efficiency and lift-drag ratio. Thus, to search for the best configuration parameters, a Kriging surrogate model based multi-objective genetic algorithm is applied to design the lifting body shape, in which the volume efficiency and lift-drag ratio are taken as the two conflict objectives under the constraints of the longitudinal stability and vehicle volume. Numerical results show the efficiency of the method and a uniform Pareto front was obtained. The volume efficiency and lift-drag ratio of the typical optimized shape have increased by 17.31% and 11.94%, respectively, when compared with the baseline. Differences of the results gained from the Kriging surrogate model and real physical model are less than 4%. Furthermore, the influences of leading edge blunting on aerodynamic character are researched. The results indicate that, the lift-drag ratio of the lifting body decreases significantly with the increase of blunting radius. It is also found that the optimized results can be extrapolated to leading edge blunting shapes when aerodynamic character is the unique concern.