Gas Turbine Heat Exchanger Mount Assembly with Movable Pin
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Solution Overview
Problem
Existing mount assemblies for surface air-oil heat exchangers in gas turbine engines face challenges such as difficulty in assembly, limited thermal expansion accommodation, imprecise frictional force control, and lack of a fire-proof boundary, particularly due to complex access requirements and material tolerance issues.
Innovation Solution
A mount assembly featuring a support bracket with a laterally movable pin body, rubber and steel washers for precise alignment, and springs for restoring force, allowing for centralized reassembly and accommodating thermal displacement while ensuring a fire-proof seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a disc spring and plain washer are used to accommodate thermal expansion, then thermal expansion is accommodated, but the control of frictional force through washer pre-load is imprecise
Solution Approach 1:
The patent changes the physical state and parameters of the resilient element from a disc spring with washer pre-load to a viscoelastic polymer material whose frictional characteristics can be precisely controlled through material composition and formulation, enabling accurate control of frictional force to maintain clamping force on the heat exchanger
Solution Approach 2:
The patent uses a composite resilient element combining viscoelastic polymer material with specific frictional properties, integrating both the thermal expansion accommodation function and the precise frictional force control function into a single material system rather than separate components
2Adaptability or versatility
If a bracket with lateral slot and disc spring is used, then thermal expansion is accommodated, but assembly difficulty increases due to complex access requirements
Solution Approach 1:
The patent merges the thermal expansion accommodation function and the frictional force control function into a single resilient element component, eliminating the need for separate disc springs, washers, and lateral slots, thereby simplifying the assembly process and reducing access requirements
Solution Approach 2:
The patent extracts and eliminates unnecessary components such as the lateral slot, disc spring, and plain washer from the assembly, retaining only the essential resilient element that performs both required functions, thus simplifying the overall structure and assembly procedure
3Strength
If a resilient element with high pre-load is used, then clamping force is maintained, but material property variation and tolerance stack-up affect SAOHE life
Solution Approach 1:
The patent changes the approach from mechanical pre-load through rigid washers to controlled frictional forces through viscoelastic polymer material properties, where the frictional characteristics are inherent to the material and less sensitive to dimensional tolerances and material property variations
Solution Approach 2:
The patent employs a resilient element made of viscoelastic polymer material that provides flexible, compliant contact surfaces, reducing stress concentrations and improving the reliability and life of the bonded SAOHE through more uniform force distribution
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 simplifies assembly and reassembly, accurately controls thermal expansion, and provides a fire-proof seal, enhancing the reliability and maintainability of the heat exchanger mounting system.
Implementation Method 1
a spring that in use can apply a restoring force to the pin body opposed to its lateral movement relative to the support bracket
Implementation Method 2
a spring that in use can apply a restoring force to the pin body opposed to its lateral movement relative to the support bracket
Implementation Method 3
The mount assembly includes a first resilient element, arranged between the support bracket and the pin body, having a first frictional force
Implementation Method 4
In use the SAOHE is subject to thermal expansion and contraction, which may be different from the expansion and contraction of the fan casing. The mounting features of the SAOHE must therefore be designed to accommodate this thermal expansion
Data Source
AI summary
A mount assembly for attaching a heat exchanger to a casing of a gas turbine engine comprises a support bracket and a pin body, the pin body laterally moveable in use relative to the support bracket. The assembly further comprises a spring that in use can apply a restoring force to the pin body opposed to its lateral movement relative to the support bracket.