Exergy-Based Formulation for Aircraft Aeropropulsive Performance Assessment: Theoretical Development

TLDR

Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for an efficient design process. A theoretical formulation based on exergy management is proposed for assessing the aeropropulsive performance of future aircraft configurations. The formulation combines a momentum balance with a fluid‑flow analysis based on the first and second laws of thermodynamics, linking exergy supplied by propulsion and its partial destruction to aircraft mechanical equilibrium while characterizing recoverable mechanical and thermal outflows and identifying irreversible work‑potential‑destroying phenomena. When applied to unpowered configurations, the formulation links to known far‑field drag expressions and demonstrates that their theory can be expressed in exergy terms, and because it does not separate thrust and drag, it is particularly suitable for evaluating highly integrated aeropropulsive concepts such as boundary‑layer ingestion.

Abstract

Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for an efficient design process. A theoretical formulation based on exergy management is proposed for assessing the aeropropulsive performance of future aircraft configurations. It consists of the combination of a momentum balance and a fluid flow analysis involving the first and second laws of thermodynamics. The exergy supplied by the propulsion system and its partial destruction within the control volume is associated with the aircraft mechanical equilibrium. Characterization of the recoverable mechanical and thermal outflows is made along with the identification of the irreversible phenomena that destroy their work potential. Restriction of the formulation to unpowered configurations yields connections to some well-known far-field drag expressions and shows that their underlying theory can be related to exergy considerations. Because the exergy balance does not rely on the distinction of thrust and drag, it is especially suitable for the performance evaluation of highly integrated aeropropulsive concepts like boundary-layer ingestion.