Abstract: It is the key for the air-breathing hypersonic vehicle direct force tests to separate the external and internal aerodynamic loads highly coupled on the model. In order to explore the related design technologies，a circular cross section venting model is taken as?research?object. The external and the internal separation by the independent external and internal parts is realized，and the conduct problem between the external and internal parts is solved by CAD-aided designing the parts clearances and the balances，especially the open positions and sizes of the parts clearances sizing. The cross-flow problem between the external and internal flow is solved by the soft packing seal，the error factors which may affect the test result precision are discussed and a wind tunnel test at Mach 6 is conducted. The contrastive analysis of the typical tests results show that，while the open positions and sizes of the parts clearance are proper and the balance stiffness is large，the external and internal parts have non-contact and non-force transfer. Adopting soft packing seal，the external and internal have not cross-flow and the interference is little. The results of the test indicate that，the test system design is successful，the external and internal aerodynamic loads can be separated from each other in physics，and the measurement error can be kept in about 4% and 3%，respectively.

Key words: Hypersonic；Wind tunnel tests；Model design；Balance；External and internal decoupling；CAD-aided design；Soft seal

摘要： 在模型上将高度耦合的内外流气动力载荷分开，是吸气式高超声速飞行器直接测力试验的关键。为探索相关设计技术，以圆截面通气模型为研究对象，通过相互独立的内/外流部件实现内外流分离；通过计算机辅助内/外流部件间隙与天平设计，特别是内/外流部件间隙开口位置与尺寸确定，来解决内/外流部件接触问题；通过软填料密封解决内外流窜流问题，并对试验干扰因素进行了分析，在Ma=6条件下开展了验证试验。典型试验对比结果表明，部件间隙开口位置和尺寸适当、天平刚度较大时，内/外流部件无接触、不传力；间隙开口采用软填料密封，内外流不窜流、干扰小。试验证明，该系统设计是成功的，能从物理上将内/外流气动力载荷分开，测量误差可分别控制在3%、4%左右。

关键词: 高超声速；风洞试验；模型设计；天平；内外流解耦；计算机辅助设计；软密封