Boundary Layer Ingestion Fan Powered by External Engine Core
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Solution Overview
Problem
Boundary Layer Ingestion (BLI) propulsion systems face challenges such as higher weight, increased complexity, and aircraft balance issues, preventing their implementation on commercial aircraft despite potential for fuel-burn reduction.
Innovation Solution
An aircraft configuration with a BLI fan coupled to the tail section and powered by an engine core positioned externally via a pylon or wing, using a mechanical or hydraulic drive system to ingest boundary layer airflow, improving engine efficiency and reducing weight and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the engine core is collocated with the BLI fan, then the propulsion system can be more compact, but the aircraft balance and safety are compromised
Solution Approach 1:
The propulsion system is divided into two separate components: the engine core and the BLI fan. The engine core is positioned externally (on the wing or fuselage) while the BLI fan is mounted on the tail section, allowing each component to be optimized independently for its specific function and location requirements.
Solution Approach 2:
A power transmission system (mechanical driveshaft or hydraulic drive) acts as an intermediary to transmit power from the externally positioned engine core to the BLI fan on the tail section, enabling the separated configuration while maintaining functional connection.
2Reliability
If the engine core is positioned externally away from the BLI fan, then the aircraft balance and safety are improved, but the power transmission system becomes more complex
Solution Approach 1:
A hydraulic drive system is used to transmit power from the engine core to the BLI fan over the distance required for optimal aircraft balance. The hydraulic system efficiently transmits power through fluid pressure while isolating the mechanical components, reducing vibration and mechanical complexity.
Solution Approach 2:
The patent offers two options: using a mechanical driveshaft system or a hydraulic drive system. The hydraulic option replaces complex mechanical power transmission with a more compact and reliable hydraulic system, reducing mechanical complexity while maintaining power transmission capability.
3Reliability
If the engine core is positioned externally, then the maintenance and safety are improved, but the overall system weight may increase
Solution Approach 1:
Separating the engine core from the BLI fan allows the engine core to be positioned in an externally accessible location for easier maintenance while the BLI fan remains in its optimal aerodynamic position on the tail section, minimizing the need for additional structural weight.
Solution Approach 2:
The power transmission system is designed to minimize weight while effectively transmitting power over the required distance. The hydraulic system in particular offers a weight-efficient solution compared to equivalent mechanical driveshaft systems.
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 enhances fuel efficiency, reduces emissions, and improves aircraft balance and safety by separating the engine core from the BLI fan, allowing for more efficient thrust generation and lower maintenance costs.
Implementation Method 1
applying the power to a mechanical driveshaft system or a hydraulic drive system to drive a boundary layer ingestion (BLI) fan
Implementation Method 2
receiving first power from a first engine core coupled externally to a fuselage. The method also includes receiving second power from a second engine core coupled externally to the fuselage
Implementation Method 3
Boundary Layer Ingestion (BLI) propulsion typically involves placing an intake of a propulsion system close to a skin (e.g., one or more external surfaces) of a fuselage of an aircraft, such that lower velocity airflow (e.g., boundary layer airflow) close to the skin of the fuselage can be ingested by the intake
Implementation Method 4
The BLI fan is coupled to a tail section of the fuselage and aft of the engine core... driving the BLI fan causes the BLI fan to generate thrust
Data Source
AI summary
An aircraft includes a fuselage having a tail section and an engine core coupled via an external pylon to the fuselage. The aircraft further includes a boundary layer ingestion (BLI) fan coupled to the tail section of the fuselage and coupled via a shaft to the engine core.