Partial Height Heat Exchanger Vanes with Flow Modifiers
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Solution Overview
Problem
Traditional heat exchangers face design constraints that inhibit performance, increase size and weight, and limit structural reliability, particularly at high temperatures, due to continuous vanes causing pressure loss and thermal stress.
Innovation Solution
The use of additively manufactured partial vanes with flow modifiers that divert fluid flow around the leading edges of vanes, reducing thermal stress and pressure loss, while maintaining efficient heat transfer by concentrating vanes upstream of the counterflow core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous vanes are used from inlet to core and core to outlet, then heat transfer surface area is increased, but pressure loss increases significantly due to smaller hydraulic diameter at inlet
Solution Approach 1:
The vane structure is segmented into partial vanes that extend only from the inlet to the core region, rather than continuously from inlet to outlet. This segmentation allows the hydraulic diameter at the inlet to be larger, reducing pressure loss, while still providing sufficient heat transfer surface area in the core region where the majority of heat transfer occurs.
2Productivity
If vanes extend fully between parting sheets, then heat transfer surface area is maximized, but thermally induced stress increases at high temperatures
Solution Approach 1:
The vanes are extracted to be partial length, extending only from the inlet to the core region rather than fully between parting sheets. This removes the portion of vanes that would be subjected to high thermal stress near the outlet, while retaining the essential heat transfer function in the core region where temperature gradients are more favorable.
3Productivity
If crossflow plenum size is increased to accommodate continuous vanes, then heat transfer area is increased, but device size and weight increase
Solution Approach 1:
Instead of providing full-length vanes throughout the entire heat exchanger, partial vanes are used that extend only to the core region. This partial action is sufficient to achieve the majority of heat transfer (since most heat transfer occurs in the counterflow core), while minimizing the size and weight of the crossflow plenums.
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 reduces thermally induced stress, decreases pressure loss, and enhances the longevity of the heat exchanger without increasing weight, allowing for efficient heat transfer and system integration.
Implementation Method 1
flow modifiers that divert fluid flow around the leading edges of vanes, reducing thermal stress and pressure loss
Implementation Method 2
exchanging heat from a hot fluid to a cold fluid
Implementation Method 3
the majority of heat transfer occurs within the counterflow core
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A heat exchanger includes a stack (106) of flow conduits. Each flow conduit is configured to conduct a fluid. Parting sheets (124) separate adjacent flow conduits in the stack, providing heat transfer between them. Each of the flow conduits includes vanes (110, 112) extending along a vane path and between top and bottom parting sheets. The vanes are separated from one another, thereby creating flow channels. Each flow conduit also includes a plurality of flow modifiers (136), each adjacent to a corresponding leading edge of a corresponding vane, so as to cause a disrupted portion of a fluid flow to be incident upon the corresponding leading edge. Each of the flow modifiers includes an aerodynamic portion and a gap portion. The aerodynamic portion extends from at least one of the top and bottom parting sheets. The aerodynamic portion does not connect the top and bottom parting sheets due to the gap portion.