Exploration of Feasible Range for Derivative Engines Based on an Adaptive Cycle Engine

Adaptive cycle engines (ACE) offer significant advantages in multimission adaptability and throttle performance, but their multibypass architecture and novel components result in high development costs, limiting their engineering application. By deriving multiconfiguration engines based on the ACE core engine and adopting a “one engine, multiple configurations” approach, costs and risks can be shared, reducing development costs and time. However, current core engine derivative design methods fall short in addressing the coupling between cooling air extraction and turbine inlet temperature, as well as in achieving multiconstraint performance optimization. To overcome these limitations, this study develops a derivative engine performance simulation model incorporating cooling requirements and proposes a feasible-range method for operating-point determination under multiple constraints. The results show that, when cooling effects are considered, the matching behavior near the surge boundary deviates from conventional trends, with both the matched turbine inlet temperature (TIT) and physical rotational speed decreasing as the operating point approaches the surge boundary. By integrating constraints on TIT, rotational speed, surge margin, and cooling requirements, the feasible-range method enables explicit identification of safe operating regions. Using this approach, derivative designs for mixed exhaust turbofan, separated exhaust turbofan, and variable cycle engines are obtained, with TIT and rotational speed maintained at their allowable limits, allowing effective utilization of the performance potential of derivative engines under constraint-compliant conditions.