Aircraft Boundary Layer Suction via Air Conditioning Integration
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Solution Overview
Problem
Existing methods for suctioning air from an aircraft's boundary layer to reduce aerodynamic frictional resistance are hindered by parasitic weight and energy constraints, as well as additional aerodynamic resistances caused by air outlets, which worsen the aircraft's aerodynamic properties.
Innovation Solution
Integrating the boundary layer suction system with the aircraft's air-conditioning system, where the suctioned air is fed into the air mixer unit and discharged jointly with the exhaust air, reducing the need for bleed air from the power plant and eliminating the need for a separate outlet, thereby minimizing flow losses and aerodynamic resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a separate outlet is added to discharge suctioned air from the boundary layer, then the aerodynamic frictional resistance is reduced, but additional aerodynamic resistances and flow losses are generated
Solution Approach 1:
The patent merges the boundary layer suction system with the air-conditioning system by routing the suctioned air through the air-conditioning system's existing ductwork and mixing it with recirculated air. The combined air stream is then discharged through the air-conditioning system's existing outlet, eliminating the need for a separate outlet and thereby avoiding additional aerodynamic resistances while maintaining the friction reduction benefit
Solution Approach 2:
The air-conditioning system outlet is given a dual function: it serves both its original purpose of discharging conditioned air and the new purpose of discharging suctioned boundary layer air. This multi-functionality eliminates the need for additional dedicated outlets, reducing aerodynamic drag while achieving both climate control and boundary layer management
2Force
If air is accelerated above flow speed at the outlet to reduce resistance, then aerodynamic properties improve, but additional energy is consumed
Solution Approach 1:
The suctioned boundary layer air is utilized as a useful resource by feeding it into the air-conditioning system where it is mixed with recirculated air and discharged. This self-service approach eliminates waste and reduces the need for additional energy-consuming acceleration systems, as the air is productively reused rather than discarded
3Force
If the boundary layer suction system operates independently with a separate outlet, then frictional resistance is reduced, but the system complexity and parasitic weight increase
Solution Approach 1:
The patent combines two previously independent systems - the boundary layer suction system and the air-conditioning system - into an integrated system. By routing the suctioned air through the air-conditioning system's existing ductwork and utilizing its outlet, the patent eliminates the need for separate outlets and reduces overall system complexity while maintaining the friction reduction benefit
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 integration reduces power plant losses and total exhaust air quantity, maintaining aerodynamic efficiency while avoiding additional flow losses typically associated with surface outlets, resulting in an improved flow-energetics balance.
Implementation Method 1
suctioning of the boundary layer neighboring the surface of the aircraft into the inside of the aircraft
Implementation Method 2
The aerodynamic frictional resistance of laminar boundary layer flows is significantly smaller than that of turbulent boundary layer flows
Implementation Method 3
The air quantity suctioned is discharged to the atmosphere jointly with the exhaust air of the air-conditioning system
Implementation Method 4
the air may be accelerated to a speed which is somewhat above the flow speed at the outlet
Data Source
AI summary
A method for suctioning the boundary layer at the surface (1) of an aircraft having an air-conditioning system (4), at whose flow-critical points of the surface multiple suction openings (2) are provided, the air quantity suctioned via these being discharged to the atmosphere again via at least one outlet (7) placed in a way favorable for flow, the air quantity suctioned from the surface (1) being fed to the air-conditioning system (4) of the aircraft, via whose outlet (7) the air quantity suctioned is discharged to the atmosphere together with the exhaust air of the air-conditioning system (4), to reduce flow losses.