A Study of Morphing Wing Effectiveness in Fighter Aircraft using Exergy Analysis and Global Optimization Techniques

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Virginia Tech

This thesis work presents detailed results of the application of energy- and exergy-based methods to the integrated synthesis/design of an Air-to-Air Fighter (AAF) aircraft with and without wing-morphing capability. In particular, a morphing-wing AAF is compared to a traditional fixed-wing AAF by applying large-scale optimization using exergy- and energy-based objective functions to the synthesis/design and operation of the AAF which consists of an Airframe Subsystem (AFS-A) and Propulsion Subsystem (PS). A number of key synthesis/design and operational decision variables are identified which govern the performance of the AFS-A and PS during flight, and detailed models of the components of each of the subsystems are developed. Rates of exergy destruction and exergy loss resulting from irreversible loss mechanisms are determined in each of the AAF vehicle subsystems and their respective components.

Multiple optimizations are performed on both types of AAF for a typical fighter aircraft mission consisting of 22 segments. Four different objective functions are used in order to compare exergy-based performance measures to the more traditional energy-based ones. The results show that the morphing-wing AAF syntheses/designs outperform those for the fixed-wing aircraft in terms of exergy destroyed/lost and fuel consumed. These results also show that the exergy-based objectives not only produce the "best" of the optimal syntheses/designs for both types of AAF in terms of exergy destroyed/lost and fuel consumed but as well provide details of where in each subsystem/component and how much specifically each source of irreversibility contributes to the optimal syntheses/designs found. This is not directly possible with an energy-based approach.

Finally, after completion of the synthesis/design optimizations, a parametric study is performed to explore the effect on morphing-wing effectiveness of changing the weight and energy penalties used to model the actuations required for morphing. The results show that the morphing-wing AAF exhibits significant benefits over the fixed-wing aircraft even for unrealistic weight and energy penalties.

aircraft design, Optimization, morphing wing, exergy