Investigation of the Effects of Various Energy and Exergy-Based Objectives/Figures of Merit on the Optimal Design of High Performance Aircraft System

This thesis work shows the advantages of applying exergy-based analysis and optimization methods to the synthesis/design and operation an Advanced Aircraft Fighter (AAF) with three subsystems: a Propulsion Subsystem (PS), an Environmental Control Subsystem (ECS), and an Airframe Subsys-tem - Aerodyanmics (AFS-A) is used to illustrate these advantages. Thermodynamic (both energy and exergy), aerodynamic, geometric, and physical models of the components comprising the subsystems are developed and their interactions defined. An exergy-based parametric study of the PS and its components is first performed in order to show the type of detailed information on internal system losses. This is followed by a series of constrained, system synthesis/design optimizations based on five different objective functions, which define energy-based and exergy-based measures of performance. A first set of optimizations involving four of the objectives (two energy-based and two exergy-based) are performed with only PS and ECS degrees of freedom. Losses for the AFS-A are not incorporated into the two exergy-based objectives. The results show that as expected all four objectives globally produce the same optimum vehicle.A second set of optimizations is then performed with AFS-A degrees of freedom and again with two energy- and exergy-based objectives. However, this time one of the exergy-based objectives incorporates AFS-A losses directly into the objective. The results are that this latter objective produces a significantly better optimum vehicle. Thus, an exergy-based approach is not only able to pinpoint where the greatest inefficiencies in the system occur but produces a superior optimum vehicle as well by accounting for irreversibility losses in subsystems (e.g., the AFS-A) only indirectly tied to fuel usage.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2005

Author dc:creator

• Periannan, Vijayanand

Chair dc:contributor.committeechair

• von Spakovsky, Michael R.

Committee members dc:contributor.committeemember

• Moorhouse, David
• Nelson, Douglas J.
• Ellis, Michael W.

• exergy
• AAF
• Optimization

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-03042005-151411

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/31405