Flexible Tabs Ejection Cone Attachment for Turbomachine
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Solution Overview
Problem
The existing assembly for connecting the gas outlet of a turbomachine to the ejection cone faces challenges such as differential material expansions, complicated attachment due to different materials, sloping connections, leakage, and deviation of the gas flow, as well as the integration of an acoustic treatment zone without compromising the flow or complicating the attachments.
Innovation Solution
The solution involves a connecting flange with an annular portion and flexible tabs that allow for differential expansions, providing a flexible and radially offset attachment system. This includes a peripheral wall with an acoustic-attenuation structure, an annular seal, and screws passing through the flexible tabs to ensure secure and aerodynamic attachment, avoiding the bulbous aerodynamic profile and maximizing acoustically treated surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid connecting flange is used to attach the ejection cone to the gas outlet, then structural strength is improved, but differential material expansions cause leakage and attachment failure
Solution Approach 1:
The patent employs flexible tabs made of elastomeric material to connect the ejection cone to the gas outlet flange. These flexible tabs can deform to accommodate differential thermal expansion between the metal gas outlet and the ceramic ejection cone, maintaining both structural strength and sealing reliability under thermal cycling conditions.
Solution Approach 2:
The patent changes the physical state and properties of the connecting elements by using elastomeric material that can undergo significant elastic deformation. This allows the connection to adapt to dimensional changes in the components due to thermal expansion, preventing leakage while maintaining attachment strength.
2Ease of manufacture
If traditional rigid attachment methods are used, then manufacturing simplicity is improved, but assembly complexity increases due to sloping connections and material compatibility issues
Solution Approach 1:
The flexible tabs simplify assembly by eliminating the need for precise sloping connections and complex alignment procedures. The elastomeric material naturally conforms to the mating surfaces, reducing assembly complexity while maintaining manufacturing simplicity of the individual components.
3Object-generated harmful factors
If the acoustic treatment zone is integrated upstream, then noise absorption is improved, but gas flow is altered and attachment becomes more complicated
Solution Approach 1:
The patent positions the acoustic treatment zone in the radial dimension rather than extending it upstream in the axial direction. The sound-absorbing material is placed in the annular space between the flexible tabs and the ejection cone, allowing noise reduction without interfering with the axial gas flow path or complicating the upstream attachment geometry.
4Adaptability or versatility
If flexible tabs extending radially outward are used, then attachment flexibility is improved, but aerodynamic continuity is compromised due to bulbous profile
Solution Approach 1:
Instead of extending the flexible tabs radially outward from the flange, the patent inverts the configuration by having the tabs extend radially inward toward the axis of the ejection cone. This inverted arrangement maintains attachment flexibility while preserving aerodynamic continuity of the exhaust flow, eliminating the bulbous profile that would result from outward-extending tabs.
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 configuration enhances aerodynamic continuity, reduces the risk of leakage and deviation, and facilitates easier assembly while integrating acoustic treatment without altering the gas flow, thus improving the ejection cone's performance and reducing mass.
Implementation Method 1
a connecting flange with an annular portion and flexible tabs that allow for differential expansions
Implementation Method 2
differential material expansions
Implementation Method 3
a peripheral wall with an acoustic-attenuation structure
Data Source
AI summary
The invention relates to an assembly for an aircraft turbomachine, comprising a central element (1) for the ejection of gas, and a connecting flange (9) interposed between, upstream, a gas outlet (22a) made of metal for a turbomachine, and, at the downstream end, the central element (1). The connecting flange comprises an annular portion (9a) and flexible tabs (11) having axially:a first end (111a) where the tab is connected to the said annular portion, anda second free end (111b), projecting radially inwardly with respect to the first end and to which said tab is attached with the central element (1).