Flexible Interface Coupling for ACM Vibration Isolation
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Solution Overview
Problem
Vibrations from aircraft engines and air cycle machines (ACMs) are amplified when a heat exchanger is rigidly mounted, exceeding acceptable vibrational loads and risking icing due to subfreezing conditions in existing vibrational isolation systems.
Innovation Solution
A flexible interface coupling with a flared region and spring energized seals allows the air cycle machine to move axially and radially relative to the heat exchanger, minimizing vibration transfer and maintaining above-freezing temperatures through heated fluid circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a heat exchanger is rigidly mounted to an aircraft engine, then structural stability is improved, but vibration transfer from the engine and ACM is amplified exceeding acceptable loads
Solution Approach 1:
A flexible interface coupling is introduced as an intermediary component between the heat exchanger and the aircraft engine. This coupling includes a flexible membrane that allows relative movement while maintaining fluid connection, thereby isolating the heat exchanger from vibrational forces generated by the engine and ACM, preventing vibration amplification while maintaining structural stability.
Solution Approach 2:
The flexible interface coupling incorporates a flexible membrane made of elastomeric material that can deform elastically in response to vibrational forces. This flexible film allows the heat exchanger to be mounted near the engine while accommodating relative movements and isolating the heat exchanger from harmful vibrations, resolving the contradiction between structural stability and vibration reduction.
2Object-affected harmful factors
If a flexible interface coupling is used to isolate vibrations, then vibration transfer is reduced, but the risk of icing increases due to subfreezing conditions
Solution Approach 1:
The flexible interface coupling design merges the vibration isolation function with thermal protection by positioning the flexible membrane within the warm fluid flow path. The warm fluid circulating through the heat exchanger also passes near the flexible coupling, providing thermal protection that prevents icing of the flexible membrane while maintaining vibration isolation capabilities.
Solution Approach 2:
The system provides beforehand cushioning against icing by utilizing the warm fluid flow to pre-heat the flexible interface coupling components. This prior thermal protection ensures that the flexible membrane and surrounding structures remain above freezing temperatures even in cold operating conditions, preventing icing before it can occur while maintaining vibration reduction.
3Object-affected harmful factors
If the diffuser is allowed to move axially and radially, then vibration isolation is improved, but fluid connection stability may be compromised
Solution Approach 1:
The flexible membrane in the interface coupling acts as a dynamic seal that maintains fluid connection stability while accommodating axial and radial movements of the diffuser. This flexible film can deform elastically to maintain sealing contact during relative movements, thereby preserving both vibration isolation capabilities and fluid connection stability simultaneously.
Solution Approach 2:
The system transitions from a static rigid connection to a dynamic flexible connection that can adapt its configuration in response to vibrational forces. The flexible membrane and spring-energized seal create a dynamic sealing interface that maintains fluid connection stability during diffuser movement, enabling effective vibration isolation while preserving hydraulic integrity.
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
Effectively isolates ACMs from heat exchangers, reducing vibrations and preventing icing, while maintaining a stable fluid connection and minimizing drag.
Implementation Method 1
the radially outward facing surface of the outlet flange includes at least one spring energized seal
Implementation Method 2
a flexible interface coupling connecting the air cycle inlet to the outlet, wherein the flexible interface coupling includes a receiving portion
Implementation Method 3
maintaining above-freezing temperatures through heated fluid circulation
Data Source
Figure 1
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Figure 3
AI summary
An air cycle system for a gas turbine engine includes a heat exchanger (20) having an air cycle inlet. An air cycle machine (30) includes an air cycle machine outlet and an annular flexible interface coupling (40) connecting the air cycle inlet to the outlet. The flexible interface coupling (40) includes a receiving portion (210) having a flared region (212) across which a diameter of a heat exchanger portion increases and a landing portion (216) across which the diameter of the heat exchanger portion is maintained. An air cycle machine portion (220) is received in the receiving portion (210) and includes an outlet flange (224) and a diffuser (226) radially inward of the outlet flange (224). The outlet flange (224) includes a radially outward facing surface contacting a radially inward facing surface of the landing portion (216). The diffuser (226) is configured to move axially and radially relative to the outlet flange (224).