Trapezoidal Plate-Fin Heat Exchanger for Dead Space Reduction
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Solution Overview
Problem
Existing plate-fin heat exchangers with rectangular axial cross-sections create gaps in non-square compartments, leading to dead space that cannot be utilized, particularly in aircraft environmental control systems.
Innovation Solution
A trapezoidal-profile heat exchanger design that fills and utilizes non-rectangular spaces by stacking and brazing together layers with trapezoidal profiles, enhancing heat transfer efficiency through optimized fin placement and passage orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plate-fin heat exchangers with rectangular axial cross-section are used, then manufacturing is simplified and manufacturing precision is maintained, but dead space is created in non-square compartments reducing space utilization
Solution Approach 1:
The patent applies asymmetry by changing the heat exchanger cross-section from a conventional rectangular shape to a trapezoidal shape. This asymmetric geometry allows the heat exchanger to better fit non-square compartments and eliminates dead space gaps that occur with rectangular designs, directly resolving the contradiction between manufacturing simplicity and space utilization
2Device complexity
If plate-fin heat exchangers with rectangular axial cross section are used, then structural simplicity is maintained, but gaps occur between adjacent heat exchangers and housing creating dead space
Solution Approach 1:
The trapezoidal cross-section introduces asymmetric geometry that eliminates gaps between heat exchangers and housing walls. This shape change maintains structural simplicity while preventing dead space formation, directly addressing the contradiction between device simplicity and energy loss from unused space
3Adaptability or versatility
If rectangular cross-section heat exchangers are arranged in non-square compartments, then installation flexibility is achieved, but gaps create dead space that cannot be utilized
Solution Approach 1:
The trapezoidal cross-section provides asymmetric geometry that adapts to non-square compartments while eliminating dead space gaps. This maintains installation flexibility in various compartment configurations while improving heat transfer efficiency by utilizing 100% of the available space
Solution Approach 2:
The patent changes the dimensional geometry from rectangular to trapezoidal cross-section, creating a shape that better utilizes the three-dimensional space in non-square compartments. This dimensional change allows the heat exchanger to fill corners and gaps that would otherwise be dead space, improving productivity
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 trapezoidal heat exchanger effectively utilizes non-rectangular spaces, increasing heat transfer capabilities and reducing dead space, thereby improving the efficiency of heat exchange in applications like aircraft environmental control systems.
Implementation Method 1
Heat is transferred between the hot and cool air via the heat transfer sheets that separate the layers. In addition, to facilitate heat transfer between the layers, each of the passages can include heat transfer fins, often formed of a material with high thermal conductivity (e.g., aluminum)
Implementation Method 2
The heat transfer fins increase turbulence and a surface area that is exposed to the airflow, thereby enhancing heat transfer between the layers
Data Source
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AI summary
A heat exchanger includes a body that includes an at least two opposing surfaces (12,14) and the at least two opposing surfaces are a trapezoidal. The body of the heat exchanger also includes, an area of cross sectional flow channels (42,44) through the body. The area of cross-sectional flow channels in a direction perpendicular to the bases of the trapezoid increase or decrease between the two bases.