Nonrectangular Heat Exchanger Core for Aerospace Thermal Management

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Solution Overview

Problem

Conventional heat exchangers with rectangular cross-sectional areas are not optimal for aerospace applications, as they do not provide a compact, low-weight, and efficient means of heat transfer, leading to inefficiencies in thermal energy exchange and increased thermal stresses.

Innovation Solution

A heat exchanger with a nonrectangular cross-sectional area, featuring a plurality of cold flow layers and hot flow tubes arranged in a circular, hexagonal, or octagonal configuration, which reduces thermal stresses and ensures equal flow resistance and pressure drop across the entire cross-sectional area, accommodating high fluid pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a rectangular cross-sectional area is used for the heat exchanger core, then the tube geometry and spacing can be kept constant across the core, but the heat exchanger does not provide a compact, low-weight, and efficient means of heat transfer

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidcross-sectional geometry
Core Design Contradiction:
ProductivityVSShape

Solution Approach 1:

The patent applies spheroidality by transitioning from a rectangular cross-section to a circular cross-section for the heat exchanger core. This curvature change enables more efficient heat transfer and a more compact design while maintaining structural integrity. The circular geometry allows for optimized tube spacing and arrangement that improves thermal performance compared to rectangular configurations.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of manufacture

If a rectangular cross-sectional area is used for the heat exchanger core, then the structure is simple to manufacture, but it leads to inefficiencies in thermal energy exchange and increased thermal stresses

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidthermal stress resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the geometric parameter of the cross-section from rectangular to circular, which fundamentally alters the stress distribution characteristics. The circular geometry provides more uniform stress distribution under thermal and pressure loads, reducing peak thermal stresses and improving reliability. This parameter change also optimizes the surface-area-to-volume ratio for enhanced heat transfer efficiency.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If a rectangular cross-sectional area is used for the heat exchanger core, then the design is conventional and easy to implement, but it does not accommodate high fluid pressures efficiently

Engineering Contradiction:
Improvepressure accommodation capabilityVSAvoidcross-sectional geometry
Core Design Contradiction:
Adaptability or versatilityVSShape

Solution Approach 1:

The circular cross-section provides superior pressure accommodation compared to rectangular geometries. The curved surfaces distribute internal fluid pressures more evenly across the structure, eliminating stress concentration at corners that plagues rectangular designs. This makes the heat exchanger better suited for high-pressure aerospace applications while maintaining a compact form factor.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 nonrectangular heat exchanger design enhances thermal energy transfer efficiency, maintains consistent performance across the entire cross-sectional area, and accommodates high fluid pressures, making it suitable for aerospace applications.

Implementation Method 1

heat exchanger extending axially along centerline C and configured to allow thermal energy transfer between first fluid 12 and second fluid 14

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3722721B1Variable geometry heat exchanger
Publication Date: 2021.11.03 HAMILTON SUNDSTRAND CORP
  • EP3722721B1 patent drawingFigure 1A
  • EP3722721B1 patent drawingFigure 1B
  • EP3722721B1 patent drawingFigure 1C

AI summary

A heat exchanger (10) includes a core (15) having a nonrectangular cross-sectional area, a plurality of cold flow layers (18) centered about a centerline with each of the plurality of cold flow layers (34) separated by corresponding walls. The heat exchanger (10) also includes a plurality of hot flow tubes (34) corresponding to each of the plurality of cold flow layers.