Turbine-based combined cycle (TBCC) engines attract intensive attention due to adequate high working efficiency within the full speed range of air-breathing vehicles. Challenges of TBCC engines lie mostly in common-used components in particular the inlet system, which needs to satisfy the mass flow distribution of different sub-engines and to reconcile the performance requirement in the full speed range. In the present work, a new conceptual design methodology of the three-dimensional inward-turning TBCC inlet with twin-design points is proposed according to the basic flow field with double incident shock waves. The shock structures and flow field parameters at the high-speed design point =4 and mass flow distribution at the low-speed design point =3 both can be designed by the basic flow field. On that basis, a typical inlet model is designed and the corresponding aerodynamic performance is evaluated at two design points. Simulation results prove that the shock structure, the mass flow distribution, and the averaged throat parameters of the TBCC inlet are all consistent with the basic flow field with sufficient accuracy at twin-design points, where the maximum relative error is only 6.3%. Meanwhile, the aerodynamic performance of the inlet shows that the inlet has stable and efficient operation characteristics, which fully affirms the feasibility of the design method.

中文翻译：

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双设计点涡轮联合循环内转进气道概念设计方法及性能评价


基于涡轮的联合循环（TBCC）发动机由于在吸气式车辆的全速度范围内具有足够高的工作效率而引起了人们的广泛关注。 TBCC发动机的挑战主要在于通用部件，特别是进气系统，需要满足不同子发动机的质量流量分配，并协调全转速范围内的性能要求。在本工作中，根据双入射冲击波的基本流场，提出了一种具有双设计点的三维内翻TBCC入口的新概念设计方法。高速设计点=4处的激波结构和流场参数以及低速设计点=3处的质量流量分布均可以通过基本流场进行设计。在此基础上，设计了典型的进气道模型，并在两个设计点评估了相应的气动性能。仿真结果表明，TBCC入口的激波结构、质量流量分布和平均喉道参数在双设计点均与基本流场一致且具有足够的精度，最大相对误差仅为6.3%。同时，进气道气动性能表明，该进气道具有稳定、高效的运行特性，充分肯定了该设计方法的可行性。