双模态冲压发动机:从宽域性能优化到模态设计

Dual-mode scramjet:From performance optimization to mode-design

航班化航天运输系统的飞行包络宽、飞行任务复杂,要求其冲压发动机具有宽域、高效、推力可调节的运行能力,通过系统级性能优化实现宽域高性能,是双模态冲压发动机研究需要攻克的关键难题。本文回顾了双模态冲压发动机概念提出的背景与初衷、双模态运行机制认知以及双模态冲压发动机性能优化的探索历程,探讨了热力循环分析与宽域性能优化的关系,建议以实现飞行任务为目标,对双模态冲压发动机的运行模态进行设计,探索“基于设计”的宽域模态控制和受控模态转换技术。根据近年来发展的双模态冲压发动机等效热力过程理论,揭示了宽域性能优化若干条件,提出一个便于实现“受控模态转换”的多设计点固定几何燃烧室宽域运行方案设想。为实现宽域模态控制和受控模态转换技术,未来需建立两大能力,一是基于任务约束定量解决进发匹配以及飞发匹配矛盾、建立飞发一体化的“即时按需设计”能力,二是发展受控燃烧组织技术、建立燃烧系统“即时按需设计”的能力。

The flight of airline type space launchers involves a wide range of velocity and altitude with complicated mis-sion profiles by phases.The Dual-Mode Scramjet(DMS)is required to have the capability of efficient operation in a designed profile with a large range of thrust levels,imposing a new challenge.A history overview with related knowledge and understanding of the DMs is provided in this paper,including its background and original intention,and progress in understanding its operation mechanism and performance optimization.The relationship between the thermal-dynamic cycle analysis and wide range performance optimization is discussed.Enlightened by the historical experience,we propose that the challenge could be overcome with systematic optimization to realize wide range mode-control operation with acceptable performance.Operational modes for wide range DMSs need to be designed according to a flight mission to establish a set of design-based wide-range-mode-controlling and controlled-modetransition technology.As an example,based on conclusions from the equivalent thermal-dynamic process theory,a DMs mode-control concept and future investigation directions are proposed for wide range effective operation.In order to develop wide-range mode control and controllable mode transition technology,two main capabilities need to be developed in the future.One capability is to settle down the inlet/engine matching and the airframe/engine integration issues based on mission constraints quantitatively,and to build an"immediate-demand design"capability for airframe/engine integration.Another capability is to develop controllable combustion organization technology and build an"immediate-demand design"capability for combustion systems.