Boundary Layer Suction via Aerofoil Bifurcation Slot
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Solution Overview
Problem
Boundary layers developed along wind tunnel walls cause inaccuracies in aerodynamic measurements by decelerating airflow, leading to differences between simulated and real aircraft conditions, and existing solutions require complex installations or modifications.
Innovation Solution
A suction system utilizing a pressure difference between the front and rear faces of a surface, featuring an aerofoil-shaped bifurcation element that directs fluid flow into a slot on the surface, effectively removing the boundary layer without needing pressure pumps or altering the surface, by leveraging the natural pressure difference between the inside and outside of the wind tunnel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure pumps and suction ducts are used to remove boundary layer, then boundary layer removal is achieved, but device complexity increases
Solution Approach 1:
The invention extracts and utilizes the existing pressure difference between the wind tunnel interior and exterior environment to drive boundary layer suction, eliminating the need for complex pressure pumps and suction ducts. The slot directly communicates the pressure difference to the boundary layer, achieving simple and effective boundary layer removal.
Solution Approach 2:
The system utilizes the natural pressure difference that already exists in the wind tunnel operation to perform boundary layer suction. The wind tunnel's own operating conditions provide the driving force, making the system self-sufficient without requiring additional active suction components.
2Reliability
If porous or perforated sections are installed in the ground plane, then boundary layer suction is achieved, but ease of manufacture decreases
Solution Approach 1:
The invention removes the need for complex porous or perforated surface modifications by using a simple slot geometry. The slot can be directly formed in the wind tunnel wall or model surface, dramatically simplifying manufacturing while maintaining effective boundary layer suction capability.
Solution Approach 2:
The invention changes the approach from modifying surface porosity to creating a geometric slot feature. This parameter change in the suction mechanism transforms a complex manufacturing requirement into a simple geometric form that can be easily fabricated and integrated into wind tunnel surfaces.
3Device complexity
If boundary layer is not removed, then measurement setup is simpler, but measurement precision deteriorates
Solution Approach 1:
The boundary layer is removed in advance at the location where it forms on the model surface, before it can interfere with aerodynamic measurements. This preliminary suction action ensures that the measurement area remains free from boundary layer contamination, maintaining measurement precision without complicating the overall measurement setup.
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 solution simplifies the removal process, allows control over boundary layer thickness, reduces interference with model tests, and enhances airflow quality by eliminating thick boundary layers, enabling larger model sizes and improved air intake performance.
Implementation Method 1
A suction system utilizing a pressure difference between the front and rear faces of a surface... means for providing a pressure difference between the front and the rear faces of the surface around the slot such that a suction of the boundary layer is performed through the slot by said pressure difference
Implementation Method 2
a bifurcation element configured for bifurcating a mass of fluid flowing along the front face of the surface, said bifurcation element comprising an aerofoil-shaped cross-section
Data Source
Figure 1
Figure 2
AI summary
Boundary layer (6) suction system for being adapted to a surface (1) exposed to the circulation of a fluid, the system comprising a portion of said surface (1) and: - a bifurcation element (2) for bifurcating a mass of fluid flowing along the front face of the surface (1), comprising an aerofoil-shaped cross-section such that the fluid is bifurcated into a first and a second flow, - a slot (3) located on the portion of the surface (1) and upstream the leading edge (5) of the bifurcation element (2), the slot (3) communicating the front and the rear faces of the portion of the surface (1), - means for providing a pressure difference between the front and the rear faces of the surface (1) around the slot (3) such that a suction of the boundary layer (6) is performed through the slot (3) by said pressure difference.