Recent Advances in Boundary Layer Ingestion Technology of Evolving Powertrain Systems

Abstract

The increasing environmental concern during the last years is driving the research community towards reducing aviation’s environmental impact. Several strict goals set by various aviation organizations shifted the research focus towards more efficient and environmentally friendly aircraft concepts. Boundary Layer Ingestion (BLI) is currently investigated as a potential technology to achieve different design goals such as energy efficiency improvement and noise emission reductions in the next generation of commercial aircraft. The technology principle is to place the propulsive unit within the boundary layer generated by the airframe body. Although several studies showed its theoretical benefits, a multidisciplinary nature is introduced in the design phase. This imposes new challenges on the current design tools. An increasing number of publications are focusing on assessing this technology while taking into account interlinks between different disciplines. The goal of this work is to review the current state-of-the-art of BLI evaluation studies. Particular focus is given to the underlying assumptions of each work, the methodology employed, and the level of fidelity of the tools used. By organizing the available work in a comprehensive manner, the up-to-date results are interpreted. The current trends and trade-offs emerging from studies are presented. Through reviewing the ongoing published work, the next steps for further development of the methods that will assess this technology are derived.

A Review of Novel and Non-Conventional Propulsion Integrations for Next-Generation Aircraft

“…Within the extensive landscape of aeronautical research, numerous literature reviews have diligently explored the nuances of BLI and the potential integrations with non-conventional configurations. These reviews have laid a foundation by examining the benefits and challenges associated with BLI, shedding light on innovative designs such as the blended wing body, the Double Bubble D8 and propulsive fuselage concepts [200][201][202].…”

Mission-Level Design Studies for Efficient Hybrid-Electric Regional Aircraft Concepts

“…The introduction of electrification concepts opens new possibilities for aircraft designers, offering greater potential to explore innovative airframe and propulsion system designs [11]. Noteworthy technological advancements include the investigation of distributed propulsion systems combined with novel technologies such as boundary-layer ingestion [12].…”

Redesign of a closed-loop high-speed facility to test distortion generators

“…Inlet distortion is the phenomenon that occurs when flow entering an aircraft engine is nonuniform either due to different flying conditions or due to the typical engine architecture. In the immediate future, Ultra High Bypass Ratio (UHBR) fan configuration, and in the long term, Hybrid Wing Body or Boundary Layer Ingesting (BLI) concepts remain promising aircraft engine architectures [1]. These engine configurations will be subjected to even much higher levels of distortion at the fan inlet than the current configurations, with possible time variations of the distortion patterns.…”