Counter-Flow Heat Exchanger Core for Low Pressure Loss
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Solution Overview
Problem
Conventional heat exchangers in aircraft engine and environmental control systems face limitations in heat transfer performance, pressure loss, and size/weight reduction, necessitating improved designs for enhanced efficiency and compactness.
Innovation Solution
A counter-flow heat exchanger core with concentric inner and outer walls featuring axially extending channels that diverge and converge, along with additional cylindrical walls and annular ring sections, optimized for flow distribution and heat transfer, manufactured using additive methods like direct metal laser sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional plate/fin construction is used in heat exchangers, then structural simplicity is maintained, but heat transfer performance is limited and size/weight reduction is difficult
Solution Approach 1:
The heat exchanger core is segmented into multiple flow paths with inner and outer walls creating distinct channels. The corrugated inner wall divides the flow into first and second sets of channels, allowing parallel heat transfer paths that increase overall heat transfer performance while maintaining compact volume.
Solution Approach 2:
The patent transitions from conventional two-dimensional plate/fin construction to a three-dimensional cylindrical counter-flow configuration. The corrugated inner wall creates axial and radial flow components, adding dimensional complexity that increases heat transfer surface area and performance within a compact cylindrical volume.
2Temperature
If conventional heat exchanger designs are used, then manufacturing simplicity is maintained, but heat transfer performance and compactness cannot be simultaneously optimized
Solution Approach 1:
The patent employs specific geometric parameters including corrugation amplitude and wavelength ratios, channel width-to-height ratios, and wall thickness proportions that optimize heat transfer performance. These parameter optimizations enable high performance while maintaining manufacturability through standardized production processes.
3Temperature
If flow paths are simplified for ease of manufacture, then manufacturing is easier, but pressure loss increases and heat transfer performance decreases
Solution Approach 1:
The corrugated inner wall creates regions of different flow characteristics - the first set of channels provides smooth flow paths for one fluid while the second set of channels between inner and outer walls provides complementary flow paths for the counter-flowing fluid. This local differentiation optimizes heat transfer while managing pressure losses through distributed flow distribution.
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 design achieves increased heat transfer performance, reduced size, and weight, while minimizing pressure drops and maintaining thermal efficiency across the heat exchanger, effectively balancing hot and cold fluid flows.
Implementation Method 1
A counter-flow heat exchanger includes a heat exchanger core including an inner wall and an outer wall radially outward and spaced apart from the inner wall
Implementation Method 2
A first flow path is defined within the inner wall and a second flow path is defined between the inner wall and the outer wall
Data Source
AI summary
A counter-flow heat exchanger comprising a heat exchanger core including an inner wall and an outer wall radially outward and spaced apart from the inner wall. A first flow path is defined within the inner wall and a second flow path is defined between the inner wall and the outer wall. The heat exchanger core includes a primary flow inlet, a primary flow outlet and a middle portion therebetween. The inner and outer walls are concentric at the primary flow inlet of the heat exchanger core. The inner wall defines a first set of channels extending axially from the primary flow inlet to the middle portion of the heat exchanger core diverging away from a radial center of the heat exchanger core. The inner wall and the outer wall define a second set of channels extending axially from the primary flow inlet to the middle portion of the heat exchanger core converging toward the radial center of the heat exchanger core.