Distributed Aircraft Propulsion With Boundary Layer Ingestion
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Solution Overview
Problem
The existing commercial aircraft configuration, a tube-and-wing design, has reached a plateau in fuel efficiency improvements, making it difficult to achieve further performance gains, and radical reconfigurations are not viable within the current air transportation infrastructure.
Innovation Solution
A mechanically-distributed propulsion system integrated into the fuselage that ingests the aircraft boundary layer, utilizing a direction-reversing transmission and propulsor fans positioned at the aft end of the fuselage to enhance fuel efficiency, while maintaining compatibility with mature air transportation systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a new aircraft configuration is adopted to improve fuel efficiency, then fuel efficiency improves, but compatibility with existing air transportation infrastructure deteriorates
Solution Approach 1:
The propulsion system is segmented into separate components: engines mounted on the fuselage and propulsor fans integrated into the wing structure. This segmentation allows the propulsion system to achieve improved fuel efficiency through boundary layer ingestion while maintaining compatibility with existing airport infrastructure and operations
Solution Approach 2:
The patent merges the propulsion function with the wing structure by integrating propulsor fans into the wing trailing edge. This merging creates a blended configuration that improves fuel efficiency while maintaining a familiar aircraft silhouette compatible with existing infrastructure
2Power
If engine efficiency is improved through traditional means, then engine performance improves, but further improvements become increasingly difficult as theoretical limitations are approached
Solution Approach 1:
The system dynamically utilizes the aircraft's boundary layer flow by ingesting it through the propulsor fans. This dynamic approach to propulsion, rather than static engine improvements, provides a new pathway for efficiency gains without approaching theoretical limitations of traditional engine design
Solution Approach 2:
The propulsor fans act as intermediaries between the engine power output and the aircraft propulsion. They convert mechanical power from the engines into additional thrust by accelerating the ingested boundary layer, providing an efficient power multiplication mechanism that bypasses traditional engine efficiency limitations
3Force
If large fans are used for propulsion, then thrust capability improves, but nacelle drag and propulsor weight increase
Solution Approach 1:
The propulsor fans are positioned locally at the wing trailing edge where they can effectively ingest the boundary layer. This local positioning allows smaller fans to generate equivalent thrust compared to large centralized fans, reducing both weight and drag while maintaining thrust capability
Solution Approach 2:
The propulsion system transitions from a traditional under-wing engine configuration to a distributed configuration along the wing trailing edge. This dimensional redistribution allows multiple smaller propulsors to collectively provide the required thrust with reduced individual and cumulative drag and weight
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration achieves a 71% reduction in fuel burn, 60 dB reduction in noise, and 87% reduction in low-temperature oxidation NOx, with improved engine accessibility and reduced fan nacelle weight, while allowing for optimized boundary layer ingestion and reduced fan pressure ratios.
Implementation Method 1
a fuselage may be provided that improves aircraft fuel efficiency by integrating a propulsion system into the fuselage in a way that enables ingestion of the aircraft boundary layer
Implementation Method 2
an engine to generate a mechanical drive power; a drive shaft operatively coupled to the engine to receive the mechanical drive power
Implementation Method 3
a direction-reversing transmission having a first rotating shaft and a second rotating shaft, the first rotating shaft operatively coupled to the drive shaft to receive the mechanical drive power, wherein the direction-reversing transmission is configured to redirect the mechanical drive power received at the first rotating shaft from a first direction to face a second direction at the second rotating shaft
Implementation Method 4
a propulsor fan coupled to the second rotating shaft to convert the mechanical drive power into thrust
Data Source
AI summary
An aircraft with an integrated boundary layer ingesting propulsion having a mechanically-distributed propulsion system. The mechanically-distributed propulsion system may include an engine to generate a mechanical drive power, a drive shaft, a direction-reversing transmission, and a propulsor fan. The drive shaft may be operatively coupled to the engine to receive the mechanical drive power. The direction-reversing transmission may have a first rotating shaft and a second rotating shaft, the first rotating shaft operatively coupled to the drive shaft to receive the mechanical drive power, which is configured to redirect the mechanical drive power received at the first rotating shaft from a first direction to face a second direction at the second rotating shaft. The propulsor fan may be coupled to the second rotating shaft to convert the mechanical drive power into thrust.