面向运载火箭栅格舵的最优操纵效率特征与宽速域气动优化设计方法

Optimal control efficiency characteristics and wide-speed-range aerodynamic design optimization method for grid fins of launch vehicle

宽速域栅格舵设计是目前运载火箭子级重复使用的关键技术之一。栅格舵在火箭一子级返回飞行过程中经历亚、跨、超声速等多个速域,在不同速域下表现出截然不同的操纵效率和气动特性,甚至相互矛盾,使得高效率的栅格舵气动设计面临极大挑战。针对上述问题,应用基于机器学习代理模型的气动优化设计方法,分别开展了栅格舵在亚、跨、超声速典型状态的气动优化设计,获得了单个速域下的最优气动外形,并分析揭示了不同速域下栅格舵最优操纵效率的流动机制,为后续设计提供指导。由于实现最优操纵效率的流动机制不同,造成了不同速域优化解之间存在矛盾。针对上述矛盾,开展了宽速域栅格舵多目标气动优化设计,兼顾考虑亚、跨、超声速3个速域的影响,优化结果表明显著改善了栅格舵宽速域气动性能,提高了栅格舵操纵效率。

Wide-speed-range grid fins design is one of the key technologies for re-use of sub-stages of launch vehicle.In the course of a substage return flight,grid fins experience subsonic,transonic,supersonic,and other speed regimes.In different speed regimes,the control efficiency and aerodynamic characteristics of grid fins are completely different,and even contradictory,which makes the aerodynamic design of grid fins with high efficiency face great challenges.To address the above problems,this paper applies the aerodynamic design optimization method based on machine learning surrogate model to carry out aerodynamic optimization design of grid fins in subsonic,transonic and supersonic typical states respectively,and obtains the optimal aerodynamic shape in different speed regimes.The flow mechanism of the optimal control efficiency of the grid fins in different speed regimes is analyzed and revealed,which can provide guidance for the subsequent design.Because of the different optimization mechanisms of different speed regimes,there are contradictions between the optimal designs of different speed regimes.In view of the above contradictions,the multi-objective aerodynamic design optimization of wide-speed-range grid fins is carried out,taking into account the influence of sub,tran and supersonic speed regimes.The optimization results significantly improve the wide-speed-range aerodynamic performance of grid fins and improve the optimal control efficiency of grid fins.