As an evolutional concept of variable cycle engine, the adaptive cycle engine draws widely attention with high expectations. It combines a variable geometry schedule and component matching principles to demonstrate its advantages such as avoiding severe inlet spillage drag and the wide variable cycle characteristics. Thus, this paper aims at equilibrium running principle analysis on an adaptive cycle engine at variable operating modes, deriving the equilibrium running equations of an adaptive cycle engine for the first time, and exploring the physical essence of components matching principle on the basis of a newly developed nonlinear component-based adaptive cycle engine performance model. It uncovers the physical essence of components matching relationships and provides mathematical derivation of equilibrium running principles which lay theoretical foundation of the variable geometries modulation schedule and overall performance optimization on an adaptive cycle engine.@en

Supersonic civil aircraft is of a promising area in the development of future civil transport, and aircraft propulsion system is one of the key issues which determine the success of the aircraft. To get a good conceptual design and performance investigation of the supersonic civil aircraft engine, in this article, a fast, versatile as well as trust-worthy numerical simulation platform was established to analyze the Mach 4 turbine-based combined cycle (TBCC) engine concept so as to be applied to the supersonic civil aircraft. First, a quick and accurate task requirement analysis module was newly established to analyze the mission requirement of the Mach 4 supersonic civil aircraft. Second, the TBCC engine performance simulation model was briefly presented and the number of engines on the supersonic civil aircraft was analyzed, considering single engine inoperative. Third, the Stone model and the DLR method were investigated to estimate the engine jet noise and the NO x emission of the Mach 4 supersonic civil aircraft. Finally, a multiobjective optimization tool made up of a response surface method and a genetic algorithm was developed to optimize the design parameters and the control law of the TBCC engine, in order to make the Mach 4 supersonic civil aircraft engine with better performance, lower noise, and lower emissions. The uniqueness of the developed analysis tool lies in that it affords a numerical simulation platform capable of investigating the task requirement analysis module of the supersonic civil aircraft, engine jet noise prediction model, and the NO x emission prediction model, as well as a multiobjective performance optimization tool, which is beneficial for the conceptual design and performance research of Mach 4 supersonic civil aircraft’s propulsion system.@en