Turbofan Engine Sizing and Tradeoff Analysis via Signomial Programming

This paper presents a full one-dimensional core and fan flowpath turbofan optimization model, based on first principles, and meant to be used during aircraft conceptual design optimization. The model is formulated as a signomial program, which is a type of optimization problem that can be solved locally using sequential convex optimization. Signomial programs can be solved reliably and efficiently and are straightforward to integrate with other optimization models in an all-at-once manner. To demonstrate this, the turbofan model is integrated with a simple commercial aircraft sizing model. The turbofan model is validated against the Transport Aircraft System Optimization turbofan model as well as two Georgia Institute of Technology Numerical Propulsion System Simulation turbofan models. Four integrated engine/aircraft parametric studies are performed, including a multimission optimization with over 2400 variables that solves in under 4 s.