Turbofan Multiobjective-Multipoint Optimization for UAV/UCAV Applications

Purpose – The purpose of this paper is to present a multi-objective and multi-point optimization method to support the preliminary design of an unmixed turbofan mounted on a sample UAV/UCAV aircraft. Design/methodology/approach – An in-house multi-objective evolutionary algorithm, a flight simulator and a validated engine simulator are implemented and joined together using object-oriented programming. Findings – Optimal values are found of the pressure ratio and corrected mass flow of both the engine fan and compressor as they operate in on/off design conditions (multipoint approach), as well as the engine by-pass ratio, that contextually minimize time and engine fuel consumption required to cover a fixed trajectory (mission profile). Furthermore, the optimal distribution of the thermodynamic quantities along the trajectory is determined. Research limitations/implications – The research deals with a preliminary design of an engine, therefore no detailed engine geometry can be found. Practical implications – The paper shows how a multiobjective and multipoint approach to the design of an engine can affect the choice of the engine architecture. In particular, major practical implications regard how the mission profile can affect the choice of the design point: in fact, there is no longer a definitive design point but the design of a UAV/UCAV should be addressed as a function of the mission profile. Originality/value – The paper presents a multiobjective and multipoint approach to engine optimization as a function of the mission profile.