Exergy-Based Performance Assessment of a Blended Wing–Body with Boundary-Layer Ingestion

TLDR

Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for efficient design processes. A theoretical formulation based on exergy management is proposed for assessing the aerothermopropulsive performance of future aircraft configurations. The authors develop and numerically implement a FORTRAN‑based exergy formulation that postprocesses Reynolds‑averaged Navier–Stokes solutions to evaluate a simplified two‑dimensional blended wing–body with boundary‑layer ingestion, addressing conventional drag/thrust bookkeeping challenges. The analysis shows the blended wing–body wastes less than 3 % exergy in its wake/jet, achieves about 1.5 % fuel savings from upstream heat transfer, and demonstrates the overall advantage of a single‑currency exergy approach.

Abstract

Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for efficient design processes. A theoretical formulation based on exergy management is proposed for assessing the aerothermopropulsive performance of future aircraft configurations. The theoretical formulation has been numerically implemented in a FORTRAN code to postprocess Reynolds-averaged Navier–Stokes flow solutions. First, the exergy formulation is presented, and then the approach is applied to assess the performance of a simplified (two-dimensional) blended wing–body configuration with boundary-layer ingestion. The challenge of applying conventional drag/thrust bookkeeping is discussed, and the pertinence of the formulation is thereby reinforced. It is shown that this architecture wastes very little exergy in its wake/jet by exhibiting an exergy-waste coefficient lower than 3% in steady flight. Finally, heat transfer upstream of the propulsion system is found to yield an approximate 1.5% fuel saving. Overall, the benefit of the single-currency aspect of the exergy analysis is highlighted.