Wave Spring Bracket for Gas Turbine Heat Exchanger Thermal Growth
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Solution Overview
Problem
The mounting of surface coolers in gas turbine engines faces challenges due to thermal growth exceeding that of surrounding components, requiring mounting brackets and systems that provide both mechanical strength and accommodate thermal expansion.
Innovation Solution
A surface cooler assembly featuring a linear wave spring disposed radially between hook rails, polymer wear materials on the hook rails, and a support bracket with fasteners and stiffening ribs, along with a lock plate to fix the end plate circumferentially, allowing for thermal expansion while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If surface coolers are mounted using rigid brackets, then mechanical strength is sufficient, but thermal growth accommodation is insufficient
Solution Approach 1:
The mounting bracket incorporates a wave spring that transforms the rigid structure into a dynamic system capable of accommodating thermal expansion. The wave spring compresses and expands radially in response to thermal growth, allowing the bracket to maintain mechanical strength while adapting to dimensional changes in the surface cooler.
Solution Approach 2:
The wave spring changes its physical parameters (compression distance, radial position) in response to thermal expansion. By allowing parameter changes in the bracket's geometry through the spring mechanism, the system accommodates thermal growth while maintaining structural integrity and mechanical strength.
2Adaptability or versatility
If the bracket is made flexible to accommodate thermal growth, then thermal growth accommodation is improved, but mechanical strength is reduced
Solution Approach 1:
The wave spring provides a dynamic solution that maintains strength while enabling flexibility. The spring's elastic properties allow it to deform under thermal load while maintaining mechanical integrity, preventing permanent deformation or failure that would occur with purely flexible materials.
Solution Approach 2:
The wave spring acts as a pre-configured cushioning element that anticipates thermal expansion forces. The spring is pre-compressed to provide immediate resistance to thermal growth, cushioning the system against sudden dimensional changes while maintaining the ability to accommodate gradual expansion.
3Reliability
If friction is increased to reduce vibration, then vibration damping is improved, but thermal expansion freedom is reduced
Solution Approach 1:
The wave spring creates a dynamic interface that provides frictional damping while maintaining thermal expansion freedom. The spring's radial movement allows controlled friction between contact surfaces, damping vibrations through energy dissipation while the overall mechanism remains free to expand thermally.
Solution Approach 2:
The wave spring acts as an intermediary element between the bracket and surface cooler, mediating the interaction between frictional damping and thermal expansion. The spring transmits damping forces while allowing thermal growth, separating the functions of vibration control and thermal accommodation.
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 manages thermal growth by providing frictional damping and pre-loading, reducing vibration and allowing circumferential movement, thus ensuring secure and efficient cooling while accommodating thermal expansion.
Implementation Method 1
The linear wave spring disposed radially between the surface cooler hook rails and the bracket hook rails provides frictional damping
Implementation Method 2
A linear wave spring disposed radially between the surface cooler hook rails and the bracket hook rails
Implementation Method 3
surface coolers can effectively aid in managing various gas turbine thermal loads... fan bypass ducts on high bypass turbofan aircraft engines can act as effective heat sinks
Implementation Method 4
the internal and external thermal loads experienced by surface coolers often result in thermal growth in excess of surrounding gas turbine engine components and structures
Data Source
Figure 1
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AI summary
A surface cooler assembly (8) includes at least one surface cooler (41) comprising surface cooler hook rails (52) extending circumferentially the length of the surface cooler (41) and including axially extending (52B) and radially extending (52A) portions. The surface cooler assembly (8) also includes at least one support bracket (48) comprising bracket hook rails (50) extending circumferentially the length of the support bracket (48) and including axially extending (50B) and radially extending (50A) portions. The support bracket (48) and surface cooler (41) are contoured in a circumferential direction. Each of the surface cooler hook rails (52) contacts a bracket hook rail (50).