Flexible Interface Coupling for Air Cycle Machine 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 potentially causing icing due to subfreezing conditions.
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 passages.
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 to the heat exchanger increases, causing harmful vibrations to exceed acceptable loads
Solution Approach 1:
A flexible coupling is introduced as an intermediary component between the heat exchanger and the aircraft engine. This flexible coupling acts as a mediator that transmits necessary mechanical connections while blocking the transmission of harmful vibrations, thus resolving the contradiction between structural stability and vibration reduction
Solution Approach 2:
The patent employs a flexible coupling with bellows-like structures and flexible membranes to create a vibration-isolating interface. These flexible elements maintain structural connectivity while absorbing and dampening vibrational energy, preventing vibration transfer to the heat exchanger
2Object-generated harmful factors
If the air cycle machine is vibrationally isolated from the heat exchanger, then harmful vibrations are reduced, but the complexity of the coupling system increases due to the need for flexible interface components
Solution Approach 1:
The flexible coupling utilizes bellows-like structures and flexible membranes that provide vibration isolation through their inherent flexibility. These elements achieve vibration reduction without requiring complex active control systems or multiple separate components, thus minimizing system complexity while maintaining effectiveness
3Object-affected harmful factors
If heated fluid passages are added to maintain above-freezing temperatures, then icing is prevented, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The flexible coupling structure is designed to serve multiple functions simultaneously: it provides vibration isolation, maintains structural flexibility, and incorporates heated fluid passages for anti-icing protection. By integrating these functions into a single component rather than adding separate systems, manufacturing complexity is reduced
Solution Approach 2:
The heated fluid passages are integrated within the walls of the flexible coupling structure itself, nesting the thermal protection function within the existing mechanical structure. This eliminates the need for separate external heating systems and reduces overall manufacturing complexity
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 effectively isolates the ACM from the heat exchanger, reducing vibrations and preventing icing, while maintaining a fluid connection and ensuring operational efficiency.
Implementation Method 1
spring energized seal
Implementation Method 2
vibrations from both the ACM and the heat exchanger are combined together via vibrational transfer from the ACM to the heat exchanger, amplification of the vibrations within the heat exchanger can result
Data Source
AI summary
An air cycle system for a gas turbine engine includes a heat exchanger having an air cycle inlet. An air cycle machine includes an air cycle machine outlet and an annular flexible interface coupling connecting the air cycle inlet to the outlet. The flexible interface coupling includes a receiving portion having a flared region across which a diameter of a heat exchanger portion increases and a landing portion across which the diameter of the heat exchanger portion is maintained. An air cycle machine portion is received in the receiving portion and includes an outlet flange and a diffuser radially inward of the outlet flange. The outlet flange includes a radially outward facing surface contacting a radially inward facing surface of the landing portion. The diffuser is configured to move axially and radially relative to the outlet flange.