Helical Flow Heat Exchanger for Low Pressure Drop
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Solution Overview
Problem
Existing heat exchangers for gas turbine engines face challenges in achieving high heat transfer effectiveness while minimizing pressure drop, leading to inefficiencies and weight issues, particularly in meso-scale and micro-scale engines where portability and efficiency are critical.
Innovation Solution
A mixed-mode heat exchanger with overlapping helical flow paths and a radial configuration, featuring counter-flow and co-flow heat transfer, maximizes heat transfer effectiveness while minimizing pressure drop, using a chessboard-like pattern of hot and cool gas flow to optimize heat exchange and reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional heat exchanger designs are used to maximize heat transfer effectiveness, then heat transfer performance is improved, but pressure drop increases significantly
Solution Approach 1:
The patent introduces a radial dimension to the flow paths, transforming conventional axial or linear flow configurations into radial-inward and radial-outward flows. This dimensional change allows heat transfer surfaces to be arranged concentrically, increasing the effective heat exchange area without proportionally increasing flow path length, thereby improving heat transfer effectiveness while maintaining lower pressure drop
Solution Approach 2:
The heat exchanger employs curved, radial flow paths instead of straight linear paths. The radial configuration with concentric heat transfer surfaces creates optimized flow patterns that reduce flow resistance and pressure drop while maximizing the heat transfer area utilization, directly addressing the contradiction between heat transfer effectiveness and pressure drop
2Weight of stationary object
If heat exchanger size is reduced for portability in meso-scale engines, then weight and size are improved, but heat transfer effectiveness deteriorates
Solution Approach 1:
The patent implements a nested concentric configuration where heat transfer surfaces are arranged in radial layers. The radial-inward and radial-outward flow paths are nested within each other, allowing maximum heat transfer area to be packed into a compact volume. This nesting approach enables high heat transfer effectiveness in a small, lightweight package suitable for portable meso-scale engines
Solution Approach 2:
By utilizing the radial dimension, the patent achieves three-dimensional heat transfer surface arrangement that maximizes heat exchange area within a compact footprint. This spatial optimization allows the heat exchanger to maintain high effectiveness while minimizing weight and size for portable applications
3Loss of energy
If heat exchanger complexity is increased to optimize heat transfer, then heat transfer effectiveness is improved, but device complexity and weight increase
Solution Approach 1:
The heat exchanger is divided into distinct functional segments: a housing, a core component containing the radial flow paths, and integrated heat transfer surfaces. This segmentation allows each component to be optimized independently while maintaining overall simplicity, achieving high heat transfer effectiveness without excessive complexity or weight
Solution Approach 2:
The patent merges the heat transfer surfaces with the flow path structure itself, creating an integrated design where the radial walls serve dual purposes as both flow boundaries and heat transfer surfaces. This merging eliminates separate heat transfer components, reducing device complexity and weight while maintaining high heat transfer effectiveness
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 achieves high thermal efficiency, tripling the cycle efficiency of meso-scale gas turbines and reducing weight, making the system suitable for portable applications with minimal pressure drop and robustness against differential pressures.
Implementation Method 1
heat transfer between working flows while minimizing pressure drop
Implementation Method 2
counter-flow and co-flow heat transfer
Data Source
Figure 1~2
Figure 3A~4
Figure 5~7
AI summary
A heat exchanger in the form of a honeycomb with a plurality of rectangular or otherwise polygon in cross-section passages which share common walls with adjacent passages. Two or more flow paths each comprises a plurality of serially connected passages. Each flow path passes through the heat exchanger in a helical pathway, thus through one passage in a first vertical stack of passages, then through a lower passage in an adjacent second vertical stack of passages, then through a lower passage in the first vertical stack, then through a lower passage in the second vertical stack and in this helical manner to the outlet from the heat exchanger. Thus, the flow path comprises alternate passages in each vertical stack, and another flow path comprises the alternate passages in at least one of the vertical stacks not taken up by the first flow path, whereby the flow paths at least partially overlap each other thereby providing both counter-flow and co-flow.