Hybrid Wing Body Engine Cycle Design Exploration for Boundary Layer Ingesting (BLI) Propulsion Systems Under Design Uncertainty

摘要

Aerospace Systems Design Laboratory, Georgia Institute of Technology, Atlanta, GA 30332 The concept of boundary layer ingestion is an aircraft propulsion system arrangement that takes advantage of the local boundary layer at the point of intake to ingest some of the vehicle's low momentum flow and re-energize it thereby reducing total power required of the vehicle. The difficulty, however, comes from the tradeoff between the amount of ingested drag and the total pressure and temperature distortion at the fan face, which results in lower levels of thermal efficiency. This concept has been explored at some length in previous studies to show the benefit specifically for the hybrid wing body aircraft design. Most of the studies up until this point have focused primarily on the cruise point for optimization of the configuration or for studying the design benefits of the concept. The current paper presents a modeling approach that allows for the modeling of BLI at multiple design points and throughout the mission operating envelope. Furthermore, the paper presents a probabilistic engine cycle design space study for a 300 passenger HWB aircraft using the EDS design tool that explores the impacts of the various physical assumptions on the system level impacts. The results show that the system is particularly sensitive to the level of total pressure drop at the fan face. An engine sizing study shows that the level of assumed losses incurred by the engine has a large effect on the resultant size of the engine as well as on the performance of the sized engine at other assumed loss levels.