Publication Date


Document Type


Committee Members

James Menart (Committee Member), Rory Roberts (Committee Co-Chair), Mitch Wolff (Committee Co-Chair)

Degree Name

Master of Science in Mechanical Engineering (MSME)


System optimization and design of aircraft is required to achieve many of the long term objectives for future aircraft platforms. To address the necessity for system optimization a vehicle-level aircraft model has been developed in a multidisciplinary modeling and simulation environment. Individual subsystem models developed exclusively in MATLAB-SimulinkTM, representing the vehicle dynamics, the propulsion, electrical power, and thermal systems, and their associated controllers, are combined to investigate the energy and thermal management issues of tactical air vehicle platforms. A thermal vehicle level tip-to-tail model allows conceptual design trade studies of various subsystems and can quantify performance gains across the aircraft. Often one of the main objectives is system efficiency for reduction in fuel use for a given mission. System efficiency can be quantified by either a 1st or 2nd law thermodynamic analysis. A 2nd law exergy analysis can provide a more robust means of accounting for all of the energy flows within and in between subsystems. These energy flows may be thermal, chemical, electrical, pneumatic, etc. Energy efficiency gains in the transient domain of the aircraft's operation provide untapped opportunities for innovation. To utilize a 2nd law analysis to quantify system efficiencies, an exergy analysis approach is taken. This work demonstrates the implementation of a transient exergy analysis for a thermal management subsystem component found on traditional aircraft platforms. The focus of this work is on the development of a dynamic air cycle machine (ACM) model and implementation of an exergy based optimization analysis. This model is utilized in tandem with a bench top ACM experimental unit at the Air Force Research Laboratory’s Modeling, Simulation, Analysis and Testing (MSAT) lab. Individual elements, including compressor, turbines, heat exchangers and control valves have been combined to investigate the behavior of a typical ACM. The experimental test stand is designed and constructed to be used as a method to validate models developed. Combining the results gained from the simulation studies, specifically the exergy analysis, and the experimental setup, a methodology is formulated for system level optimization. By leveraging this approach, future simulation studies can be implemented on various system architectures to generate accurate models and predictive analysis.

Page Count


Department or Program

Department of Mechanical and Materials Engineering

Year Degree Awarded