翼身融合背撑发动机布局的动力短舱设计

为了解决翼身融合（BWB）背撑发动机布局的飞机-发动机流动干扰问题，依据BWB流场特征，提出背撑式动力短舱设计思想：采用轴对称短舱，结合可以减小短舱外部流动对机体影响的外罩型面和满足进气效率要求的进气道型面设计。基于本文构建的动力短舱参数化建模方法和多点优化设计方法，开展兼顾内外流的短舱综合优化设计研究，最后对设计方案安装状态流场进行分析。结果表明：提出的设计方法可以给出具有不同内外流气动特性、满足BWB背撑式发动机动力短舱多点设计要求的设计方案，巡航状态短舱外表面和全推力状态进气道最大马赫数最大可减小8.35%和11.81%，优化结果在最大推力和侧风起飞状态也具有良好的进气道性能；动力短舱安装状态消除了高速巡航飞行状态下短舱和机体之间的强激波和后体流动分离，低速大迎角状态机体外流能够为发动机提供均匀稳定的进气，进气道总压恢复系数满足设计要求。

Powered-on nacelle design on blended-wing-body configuration with podded engines

To solve the problem of aircraft-engine flow interference of Blend-Wing-Body (BWB) configuration with podded engines, this paper presents the design principles for podded nacelles based on the BWB flow characteristics. The axisymmetric nacelles should be taken into account together with the fan cowl profile which could reduce the influence of nacelle external flow on the airframe and the intake profile which meets the requirements of intake efficiency. Based on the parameterization method and multipoint optimization design method for powered nacelles established in this paper, the nacelles optimization considering both internal and external flow is carried out. Finally, the flowfield of the installed engine nacelle is analyzed. The results show that the design method proposed in this paper can provide the design options with different internal and external aerodynamic characteristics and meet the multipoint design requirements of the power nacelle for BWB with podded engines. The peak Mach number at cruise and full thrust condition can be reduced by 8.35% and 11.81% respectively to the largest extent. The optimization results also have good intake performance at maximum thrust and crosswind takeoff condition. For the installed nacelle configuration, the strong shock wave between engine and airframe and the rear body separation at high speed cruise condition is eliminated, and the airframe external flow provides uniform and stable intake for the engine at low speed condition with high angle of attack, meanwhile, the intake total pressure recovery coefficient meets the design requirements.