Aircraft Wing High Lift Device Flow Control via Air Conveying Openings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The geometric limitations and aerodynamic penalties associated with the interruption of leading edge high lift devices on aircraft wings due to engine pylon placement hinder efficient high lift generation, leading to inharmonic lift distribution and increased drag.
Innovation Solution
The introduction of openings connected to an air conveying device in the region of the high lift device interruption allows for active flow control through air suction or blowing, harmonizing flow characteristics and reducing separation, thereby enhancing lift generation without complex kinematic systems or additional deployment space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine diameter is increased to improve fuel efficiency, then the bypass ratio of the turbofan engine increases, but the engine cannot be mounted closer to the wing due to landing gear length restrictions and shock absorption characteristics
Solution Approach 1:
The wing leading edge high lift device is segmented into multiple sections: an inboard section, an outboard section, and a gap section between them. This segmentation allows the engine to be positioned closer to the wing by creating space for the engine pylon and nacelle in the gap region, while still maintaining high lift capability through the coordinated operation of the separated high lift sections
Solution Approach 2:
The high lift device extends into the gap section between the inboard and outboard sections, utilizing the spanwise dimension to overcome the physical obstruction. By extending the high lift device into this previously unusable space, the design achieves both close engine mounting and effective high lift generation
2Length of moving object
If the leading edge high lift device is interrupted to avoid collision with the engine pylon, then the engine can be mounted closer to the wing, but aerodynamic penalties occur due to inharmonic lift distribution
Solution Approach 1:
Different sections of the leading edge high lift device are given different characteristics: the inboard section has a first configuration optimized for its region, the outboard section has a second configuration optimized for its region, and they are connected through the gap section. This local optimization allows each section to perform its function while maintaining overall aerodynamic harmony
Solution Approach 2:
The gap section acts as an intermediary element between the inboard and outboard high lift sections. It provides aerodynamic continuity and harmonizes the lift distribution across the interruption, preventing the harmful inharmonic effects that would otherwise result from the discontinuity
3Volume of moving object
If a Krüger flap is used in the inboard region to reduce deployment room requirements, then less deployment space is needed compared to conventional slats, but the kinematic system becomes complex requiring frequent maintenance
Solution Approach 1:
The complex kinematic system is extracted and replaced by a simpler alternative. Instead of using a Krüger flap with its intricate mechanical linkage and rotation mechanisms, the design employs a simplified high lift device that achieves the same space-saving benefit through a more straightforward structural approach
Solution Approach 2:
The mechanical kinematic system of the Krüger flap is replaced with an alternative mechanism that reduces complexity. The new design achieves compact deployment through a different mechanical approach that requires fewer moving parts and less maintenance
4Reliability
If strakes are introduced as passive devices to delay stall, then the stall in the region of slat interruption is delayed, but unwanted drag is created before the critical angle of attack is reached
Solution Approach 1:
The high lift device configuration is made dynamic and adjustable rather than fixed. The ability to change the configuration and positioning of the inboard and outboard sections allows the system to adapt to different flight conditions, achieving stall delay without the continuous drag penalty of fixed strakes
Solution Approach 2:
The aerodynamic parameters of the high lift device are made variable. By adjusting the position, angle, and configuration of the high lift sections, the system can optimize performance for different flight regimes, achieving reliable stall delay while minimizing drag in non-critical flight conditions
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 approach enables efficient high lift generation with reduced drag and fuel burn, allowing for a closer engine placement to the wing without degrading aerodynamics, and is optimized through CFD analysis and wind tunnel testing.
Implementation Method 1
the surface element comprises an arrangement of openings in a region covering the add-on body, which openings are connected to an air conveying device for conveying air
Data Source
AI summary
A surface element, e.g. a wing, of an aircraft includes a leading edge, a high lift device arrangement positioned along the leading edge and at least one add-on body positioned in a leading edge region, wherein the high lift device arrangement is interrupted in the region of at least one add-on body for preventing collision with the add-on body and wherein the surface element includes an arrangement of openings in a region covering the add-on body, which openings are connected to an air conveying device for conveying air through the openings. Thereby an additional flap for harmonizing the flow above a pylon or other add-on body can be eliminated.