A multi-fidelity simulation method of external and internal flow has been developed using commercial software to achieve a smooth thrust of the turbine-based combined-cycle (TBCC) propulsion system. This platform enables the investigation of the flow field and performance of the TBCC propulsion system at different mode transition schemes. The integrated multi-fidelity simulation includes the inlet, turbojet engine, ramjet engine, and nozzle, providing insights into the operation process of the TBCC propulsion system during the transition from turbojet mode to ramjet mode. Three mode transition schemes are proposed: critical mode transition, constant aerodynamic interface plane (AIP) Mach number mode transition, and linear mode transition. From the perspective of TBCC inlet, the performance of the critical mode transition exhibits the best performance among these mode transition schemes, while the linear mode transition performs the worst. However, from the viewpoint of the TBCC propulsion system and the hypersonic vehicle, the performance of constant AIP Mach number mode transition is the best. The non-dimensional thrust increases almost linear from 1.0 to 1.2, enabling hypersonic vehicle to accelerate steadily during the transition from turbojet mode to ramjet mode.

中文翻译：

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基于涡轮机联合循环的入口模式过渡与平滑推力的多保真度模拟


使用商业软件开发了一种外部和内部流动的多保真度模拟方法，以实现基于涡轮机的联合循环 （TBCC） 推进系统的平稳推力。该平台可以研究 TBCC 推进系统在不同模式转换方案下的流场和性能。集成的多保真仿真包括进气口、涡轮喷气发动机、冲压喷气发动机和喷嘴，提供了对 TBCC 推进系统在从涡轮喷气模式过渡到冲压喷气模式期间的运行过程的见解。提出了三种模式转换方案：临界模式转换、恒定空气动力学界面平面 （AIP） 马赫数模式转换和线性模式转换。从 TBCC 入口的角度来看，临界模式转换的性能在这些模式转换方案中表现最好，而线性模式转换的性能最差。然而，从 TBCC 推进系统和高超声速飞行器的角度来看，恒定 AIP 马赫数模式转换的性能是最好的。无量纲推力从 1.0 增加到 1.2 几乎呈线性增加，使高超音速飞行器能够在从涡轮喷气发动机模式过渡到冲压喷气发动机模式期间稳定加速。