Turbine Case Damping Seal Baffle for Cantilever Wall Vibration
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Solution Overview
Problem
Existing aircraft engine turbine case structures face challenges in managing dynamic excitation and vibration-induced stress due to the cantilevered inner walls, which can lead to crack formation and increased stress levels.
Innovation Solution
Incorporation of a compliant sheet metal damping seal baffle that contacts and moves relative to the cantilevered inner wall surfaces, providing damping and sealing functions to mitigate vibration-induced stress and deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cantilevered inner wall is used in the turbine case structure, then the structural support and gas flow direction are improved, but vibration-induced stress and deflection increase leading to crack formation
Solution Approach 1:
A damping seal baffle is introduced as an intermediary element between the cantilevered inner wall and the source of vibration. The baffle contacts the inner wall and provides damping to reduce vibration-induced stress and deflection, preventing crack formation while maintaining the structural support function of the cantilevered design
Solution Approach 2:
The damping seal baffle changes the dynamic parameters of the cantilevered inner wall by providing damping characteristics. This modifies the vibration response and stress distribution, reducing the harmful vibration-induced stress while preserving the structural integrity and support function
2Reliability
If a compliant damping seal baffle is introduced to reduce vibration-induced stress, then crack formation is prevented, but device complexity increases
Solution Approach 1:
The damping seal baffle is constructed as a compliant structure with curved segments that can flex and conform to the cantilevered inner wall. This flexible design provides effective vibration damping and crack prevention while maintaining a relatively simple geometric form that integrates smoothly into the existing turbine case structure
Solution Approach 2:
The damping seal baffle is designed as a movable component that can deflect and adapt to the dynamic motion of the cantilevered inner wall. This dynamic capability allows the baffle to maintain contact and provide damping under varying operating conditions without requiring a complex rigid structure
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 damping seal baffle effectively reduces vibration-induced stresses on the turbine case, limiting deflection and preventing crack formation while maintaining sealing integrity across varying thermal conditions.
Implementation Method 1
a damping seal baffle... configured to move relative to the first sealing surface and the second sealing surface
Implementation Method 2
The damping seal baffle may be formed by a compliant sheet metal body
Data Source
AI summary
A gas turbine engine includes a turbine section, a turbine case, an inner case, and a damping seal baffle. The turbine section extends along a rotational axis of the gas turbine engine. The turbine case includes a cantilevered inner wall. The cantilevered inner wall extends circumferentially about the rotational axis. The cantilevered inner wall extends between and to an upstream axial end and a downstream axial end. The upstream axial end is disposed at and downstream of the turbine section. The cantilevered inner wall forms a first sealing surface and a second sealing surface. The inner case extends and the damping seal baffle extend circumferentially about the rotational axis. The damping seal baffle is mounted to the inner case. The damping seal baffle is disposed in contact with one or both of the first sealing surface or the second sealing surface.