Simultaneous airframe and propulsion cycle optimization for supersonic aircraft design

Abstract

Supersonic aircraft design includes several tradeoffs, each with advantages and disadvantages. The selection of aircraft shape to meet the prescribed requirements is a nontrivial exercise in the case of commercial supersonic configurations with multiple stringent constraints. The number of discrete shape options, along with the detailed aircraft shaping, presents a difficult choice to the configuration designer. Most often, the aircraft shape is frozen, based on experience. In the case of revolutionary shapes or designs, such a choice would be suboptimal. Furthermore, unlike the subsonic designs, the propulsion cycle plays a much more important role than in the earlier stages of design in the case of supersonic configurations. This paper presents an approach for the simultaneous inclusion of airframe and propulsion system parameters in the aircraft design process. The proposed approach parameterizes the geometry in terms of several shape variables and the propulsion system in terms of representative cycle variables. Advanced genetic algorithms are developed and employed to obtain aircraft configurations and propulsion cycle parameters that simultaneously optimize several critical performance metrics including range, sonic boom loudness, and jet velocity. Results from the optimization are presented and design tradeoffs are discussed.