Aircraft Eductor Drag Modification for Boundary Layer Ingestion
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Solution Overview
Problem
Existing aircraft designs face increased drag due to fuselage boundary layers, which leads to higher fuel consumption, and current solutions like boundary layer ingestion require large, heavy engines or complex suction systems that introduce additional penalties.
Innovation Solution
A drag modification system using a manifold and eductor that generates suction at the fuselage exterior to ingest and accelerate boundary layer airflow without external fans or turbomachinery, leveraging pressurized air from existing aircraft systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If boundary layer ingestion is used to reduce drag, then fuel consumption is reduced, but large heavy engines or complex suction systems are required which add weight and complexity
Solution Approach 1:
The system uses the aircraft's existing engine exhaust as the motive fluid for the eductor, eliminating the need for separate suction systems or additional engines. The exhaust gases naturally provide the suction force needed to ingest boundary layer air through the eductor device, making the system self-sufficient without adding external heavy components
Solution Approach 2:
The eductor acts as an intermediary device that couples the engine exhaust flow with the boundary layer ingestion function. It uses the exhaust gases as a mediator to create suction and draw boundary layer air into the exhaust stream, achieving drag reduction without requiring direct mechanical connection or additional propulsion systems
2Loss of energy
If boundary layer ingestion is used to reduce drag, then fuel consumption is reduced, but large heavy engines are required which increase weight
Solution Approach 1:
The system leverages the aircraft's existing engine exhaust as the source of suction force, eliminating the need for additional heavy engines or suction systems. The exhaust gases naturally provide the necessary pressure differential to ingest boundary layer air, using an already-available resource to achieve drag reduction without adding weight
Solution Approach 2:
The invention extracts the useful function of boundary layer ingestion from the conventional approach that requires separate heavy engines or suction systems. By taking out only the essential eductor component and using existing exhaust flow, it achieves the same drag reduction effect without the associated weight penalty
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
Reduces drag by up to a factor of four and improves thrust recovery, while being retrofittable to existing aircraft designs without significant structural modifications.
Implementation Method 1
The primary fluid is a motive fluid having flow parameters to generate a suction (e.g., a negative pressure) at the secondary inlet
Implementation Method 2
receiving a boundary layer airflow into the intake plenum as a result of a negative pressure gradient effectuated by entrainment of air from the intake plenum into the eductor
Implementation Method 3
The motive fluid is to generate a suction to cause airflow to draw through the second inlet and channel the airflow to the exhaust
Data Source
AI summary
Drag modification systems for aircraft and related methods. An example system for modifying drag on an aircraft includes a boundary layer intake plenum and an eductor. The eductor defines a primary inlet to receive a primary fluid, a secondary inlet in fluid communication with the intake plenum to receive a secondary fluid entrained from the intake plenum, and an outlet to exhaust a mixed flow including the primary fluid and the secondary fluid. The primary fluid is a motive fluid having flow parameters to generate a suction at the secondary inlet.