Aircraft Engine Air Seal Structure for Rigidity and Nacelle Mounting
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Solution Overview
Problem
Conventional air sealing devices between turbomachine casing and nacelle elements in dual-flow aircraft engines face challenges in achieving high rigidity to resist air pressure while allowing for nacelle mounting, due to contradictory design constraints.
Innovation Solution
The air-tightness device incorporates protuberances that extend towards the center of the sealing portion, forming an angle of 40-60° with the tongue's direction, and is made from elastomeric material with fibrous reinforcing layers and an anti-friction outer layer, enhancing rigidity and contact with casing and nacelle elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the sealing device is designed with high rigidity to withstand air pressure, then sealing performance is improved, but the difficulty of mounting the nacelle element increases
Solution Approach 1:
The sealing device transitions from a static rigid structure to a dynamic system where the sealing portion can deform elastically during mounting, then maintains rigidity under operating pressure. The elastomeric material allows the sealing portion to adapt its shape dynamically - flexible during installation, rigid during operation.
Solution Approach 2:
The sealing device changes its physical parameters between mounting and operation phases. During mounting, the material remains in a softer, more compliant state. Under air pressure, the internal pressure causes the sealing portion to expand and become rigid, automatically adjusting its mechanical properties based on operating conditions.
2Ease of operation
If the sealing device uses elastomeric material to allow mounting, then ease of installation is improved, but rigidity under air pressure deteriorates
Solution Approach 1:
The sealing device uses pneumatic pressure from the secondary flow to activate its rigidity. The air pressure differential across the sealing portion causes it to expand and become rigid during operation, while remaining soft and flexible during installation when no pressure differential exists.
Solution Approach 2:
The sealing portion dynamically transitions between soft and rigid states based on operating conditions. During installation, it is soft and compliant. When air pressure is applied, it automatically becomes rigid to maintain the seal, eliminating the need for separate mounting and operational structures.
3Strength
If the sealing portion is made thicker to increase rigidity, then resistance to air pressure is improved, but the complexity of the device increases
Solution Approach 1:
Instead of uniformly thickening the entire sealing device, the invention concentrates material and structural reinforcement only where needed - in the sealing portion and through internal protrusions. This localized approach provides maximum rigidity where air pressure acts most strongly, while keeping other areas simple and easy to install.
Solution Approach 2:
The sealing device uses composite construction combining elastomeric material with internal protrusions and reinforcing structures. This composite design achieves high rigidity under pressure without requiring the entire device to be thick or complex, as the rigid elements are strategically positioned only where structural support is needed.
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
The solution provides increased rigidity and reduced sagging, ensuring effective sealing and minimizing air leaks, even under maximum compression, thereby improving the airtightness and performance of the propulsion assembly.
Implementation Method 1
The sealing portion is made from an elastomer material, preferably a silicone elastomer material
Implementation Method 2
it comprises at least one reinforcing fibrous layer, preferably made of polyester
Implementation Method 3
The protrusions advantageously make it possible to limit the sagging of the sealing portion of the device. They thus provide a satisfactory response to the expressed need, in particular by ensuring increased rigidity in the event of maximum compression, thanks to the support provided by these protrusions.
Implementation Method 4
The sealing portion is crossed by one or more hollow pressurization orifices. This makes it possible to reinforce the contact between the sealing portion delimiting this hollow, and the casing and nacelle elements.
Data Source
Figure 1
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Figure 4~6
AI summary
The invention concerns an air-sealing device (40) intended to be inserted between an aircraft dual-flow turbine engine casing element (16) and a nacelle element (30), the sealing device comprising an attachment tab (42) at the end of which is located a sealing portion (44) having an outer surface intended to be contacted by the casing element and the nacelle element, and an inner surface defining a cavity. The inner surface defines at least one protuberance extending inside the cavity.