Turbine Fan Cooler Assembly Thermal Growth Mounting
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Solution Overview
Problem
Current heat exchanger designs for aircraft engines are space-constrained, thermally expand due to high temperatures, and suffer from high cycle fatigue due to inadequate accommodation of thermal growth, leading to inefficiencies in heat dissipation and potential mechanical failure.
Innovation Solution
A fan casing assembly with a surface cooler mounted via a first connection assembly that fixes the cooler in all six degrees of freedom and a second connection assembly that allows circumferential thermal growth, enabling expansion and reducing fatigue through a floating connection that permits rotation about the Z-axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat exchangers are fixed rigidly to the engine to prevent movement, then high cycle fatigue from engine vibration is prevented, but thermal expansion during operation causes stress and potential failure
Solution Approach 1:
The mounting system transitions from a fully rigid fixed connection to a dynamic system that allows controlled movement. The floating connection enables the heat exchanger to expand thermally while the fixed connection prevents excessive movement, creating a balanced system that adapts to thermal conditions during operation.
Solution Approach 2:
The mounting system is divided into two distinct connection types: a fixed connection at one end and a floating connection at the other end. This segmentation allows different portions of the heat exchanger to be treated differently - one end is anchored for stability while the other end is free to expand, resolving the conflict between preventing fatigue and accommodating thermal growth.
2Area of stationary object
If the space available for heat exchangers is limited, then the engine design is compact, but newer engine technologies with more heat to dissipate become thermally constrained
Solution Approach 1:
The floating connection allows the heat exchanger to utilize thermal expansion in the circumferential direction as an additional dimension for accommodation. Rather than requiring more linear space, the system allows the heat exchanger to expand outward, effectively using the radial/circumferential dimension to resolve space constraints.
3Strength
If the heat exchanger is allowed to expand freely, then thermal stress is reduced, but the heat exchanger moves into critical zones and causes operational issues
Solution Approach 1:
The system creates a dynamic balance where the floating connection permits necessary thermal expansion while the fixed connection establishes a boundary that prevents excessive movement. This dynamic arrangement allows the heat exchanger to adapt to thermal conditions without compromising positional stability or encroaching on critical zones.
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
This design enhances heat dissipation efficiency, reduces mechanical stress, and extends component lifetime by accommodating thermal expansion while maintaining precise positioning and preventing movement into critical zones.
Implementation Method 1
heat exchangers provide a way to transfer heat away from such engines
Implementation Method 2
surface cooler that is mounted to an aft fan casing
Implementation Method 3
the heat exchangers are subject to relatively high temperatures that cause them to expand thermally, especially laterally or tangentially
Data Source
AI summary
A fan casing assembly for a turbine engine including a casing having an annular fan cooler. The annular fan cooler includes first and second connection assemblies to fix movement of the fan cooler during engine operation, while permitting circumferential thermal growth of the fan cooler without suffering from high cycle fatigue.