Bowed Circular Heat Exchanger Core for Thermal Stress Relief
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Solution Overview
Problem
Heat exchangers used in aircraft engines experience short service lifetimes due to thermal stresses and vibrations, which cause expansion, cracking, and stiffness issues, particularly at the inlet/outlet interfaces.
Innovation Solution
A heat exchanger core design featuring bowed conduits arranged around an axis, providing thermal compliance by allowing bending deformation to relieve thermal stress, and optimized through additive manufacturing for tailored dimensions and geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rigid conduit designs are used in heat exchangers, then structural strength is maintained, but thermal stress causes expansion and cracking at inlet/outlet interfaces
Solution Approach 1:
The conduit geometry is changed from straight to bowed/curved, fundamentally altering the structural parameters to enable thermal compliance. This geometric parameter change allows the conduits to accommodate thermal expansion through controlled deformation rather than rigid resistance, reducing thermal stress at critical interfaces
Solution Approach 2:
The patent applies curvature to the conduit design by incorporating bowed shapes instead of straight lines. This curvature enables the conduits to flex and deform under thermal load, providing a compliance mechanism that absorbs thermal stress and prevents cracking at the inlet and outlet interfaces
2Stress or pressure
If compliant conduit designs are used to reduce thermal stress, then thermal stress is relieved, but component stiffness decreases
Solution Approach 1:
The heat exchanger system employs different conduit geometries in different locations: bowed conduits at the core provide thermal compliance and stress relief, while straight conduits at the inlet and outlet headers maintain structural strength and stiffness. This local differentiation allows each region to optimize for its specific functional requirements
3Manufacturing precision
If additive manufacturing is used to create tailored conduit dimensions, then manufacturing precision and adaptability are improved, but device complexity increases
Solution Approach 1:
The patent integrates multiple components (inlet header, outlet header, and bowed conduits) into a single monolithic structure manufactured by additive manufacturing. This merging eliminates the need for separate manufacturing and assembly steps, reducing overall device complexity despite the sophisticated geometry required for thermal compliance
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 bowed conduit design reduces thermal stress and stiffness, enhancing the heat exchanger's performance under thermal and vibrational loads, while maintaining efficient fluid flow and heat transfer.
Implementation Method 1
The bowed conduits connect the plurality of inlets to the plurality of outlets and provide thermal compliance to the core
Data Source
AI summary
A core arrangement for a heat exchanger includes a plurality of inlets arranged around an axis, a plurality of outlets arranged around the axis, and a plurality of bowed conduits arranged around the axis. The bowed conduits are structurally independent, connect the plurality of inlets to the plurality of outlets, bow outward from the axis between the plurality of inlets and the plurality of outlets, and provide thermal compliance to the core.