Plate Fin Heat Exchanger Flange Heating for Thermal Stress Relief
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Solution Overview
Problem
Restricted thermal expansion in plate fin heat exchangers due to differing thermal expansion properties of components leads to thermally-induced stress, reducing the longevity and reliability of the device.
Innovation Solution
A mounting flange with heat transfer structures that extend into the flow path of cooling air exiting the cool air outlet region, matching the expansion rate of the core components, thereby reducing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the mounting flange is rigidly connected to the core, then structural stability is improved, but thermal stress increases due to restricted thermal expansion
Solution Approach 1:
The mounting flange incorporates a flexible membrane structure that allows thermal expansion and contraction while maintaining structural integrity. This flexible design enables the flange to accommodate differential thermal expansion between the mounting flange and the core, reducing thermal stress while preserving structural stability during operation.
Solution Approach 2:
The mounting flange is designed with material and structural parameters that allow it to change its physical state in response to temperature variations. By changing parameters such as material selection, thickness, and geometric configuration, the flange can adapt its thermal expansion characteristics to match those of the core, thereby reducing thermal stress.
2Stress or pressure
If the mounting flange is designed to accommodate thermal expansion, then thermal stress is reduced, but structural rigidity decreases
Solution Approach 1:
The flexible membrane structure provides just enough compliance to accommodate thermal expansion while maintaining sufficient rigidity to perform its structural function. The membrane is designed with optimal thickness and material properties that balance flexibility for thermal accommodation with rigidity for structural support.
Solution Approach 2:
The mounting flange transitions from a static rigid structure to a dynamic structure that can adapt its rigidity based on operating conditions. During thermal cycles, the flange dynamically adjusts its physical state to accommodate expansion and contraction, providing the necessary flexibility when needed while maintaining structural integrity.
3Stress or pressure
If different materials are used for core components, then thermal expansion rates can be matched, but manufacturing complexity increases
Solution Approach 1:
Rather than changing materials, the invention changes the physical and geometric parameters of the mounting flange (such as thickness, shape, and structural configuration) to achieve the desired thermal expansion characteristics. This approach allows thermal stress reduction while maintaining manufacturing simplicity by working with a single material system.
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 decreases thermally-induced stress on components near the hot-hot region, increasing the longevity of the heat exchanger by aligning the expansion rates of the mounting flange and core components.
Implementation Method 1
The plurality of heat transfer structures of the flange transfer heat from the cooling air (which is at its hottest when exiting the cool air outlet) to the mounting flange
Implementation Method 2
thereby causing the mounting flange to expand at a rate that is more similar to a rate of expansion of elements of the core
Data Source
Figure 1
Figure 2
AI summary
A plate fin heat exchanger includes a plate fin core (16) having a plurality of plates defining a set of hot air passages (30) extending from a hot air inlet region of the plate fin core (16) to a hot air outlet region of the plate fin core and a set of cool air passages (32) extending from a cool air inlet region of the plate fin core to a cool air outlet region of the plate fin core. The plate fin heat exchanger further includes a mounting flange (12) circumscribing the cool air outlet region. At least a portion of the mounting flange (12) has a plurality of heat transfer structures (22) that extend into a flow path of cooling air exiting the cool air outlet region of the plate fin core.