【摘要】 为降低对下方的红外信号特征，飞行器会利用机身后体部分型面，既提供对下方的红外遮蔽，也作为发动机喷流的单边膨胀面。喷流对单边膨胀面的非对称作用，可能对全机气动效率和飞行控制产生不利干扰。通过计算流体力学（CFD）分析带喷流的全机模型在不同来流条件和发动机工况下的气动性能，发现喷流在起飞状态产生较大的低头力矩，影响飞行安全，在巡航状态则增加了全机阻力，降低了推进效率。运用基于NSGA-II算法和Kriging代理模型的混合优化算法对后体膨胀面进行优化设计，通过对压力分布形态的调整，使起飞时由发动机喷流引起的低头力矩增量减少了47.6%，巡航阻力也有所降低。现有优化算法和优化策略对此类问题有较好的效果。更多还原

【Abstract】 For air vehicles which appreciate the infrared stealth performance,utilizing part of the after-body surface as the asymmetric nozzle expansion section could gain well infrared characteristic. The asymmetric effect on after-body expansion surfaces by the nozzle jet may cause some harmful effects on flight efficiency and control. CFD angysis was conducted to acquire the aerodynamic characteristics of the nozzle within model in different flight conditions and engine states. The engine jet generated massive pitch down moment in takeoff state,which affects flight safety. In the cruise state,the engine jet interaction on the after-body surfaces increased drag and reduced propulsion efficiency. Hybrid optimization algorithm based on NSGA-II and Kriging surrogate model was applied to design the after-body expansion surface. Under the promise of after-body expansion surfaces engineering achievability,and the adjustment in geometry altered the surfaces pressure distribution. Optimized configuration decreased 47.6% of the pitching moment variation which was caused by the nozzle jet during the takeoff,and the cruise drag decreased in some extent. The optimization algorithms and strategies are good at improving similar problems.更多还原