Multi-Core Heat Exchanger for Aircraft Generator Cooling

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Solution Overview

Problem

Existing cooling systems for aircraft generators and associated electronics face challenges in maintaining a stable temperature environment, particularly when compact configurations require electronics to be located outside temperature-controlled bays, and existing solutions complicate system design by increasing complexity and risking overheating of less robust components.

Innovation Solution

A parallel circuit cooling system with thermally isolated heat exchanger cores allows for the separate cooling of generators and electronics, using a multi-core heat exchanger with insulating layers to maintain distinct temperature zones, enabling the placement of electronics in close proximity to generators while preventing overheating, and utilizing pumps driven by a common source for efficient heat rejection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If electronics are placed in a temperature-controlled and pressurized bay, then the operating temperature of electronics is maintained within acceptable limits, but the distance between generator control unit and generator increases, increasing system complexity

Engineering Contradiction:
Improveelectronics operating temperatureVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The heat exchanger is divided into multiple thermally isolated cores, with a first core dedicated to cooling the generator and a second core dedicated to cooling the electronics. This segmentation allows each core to independently manage the thermal requirements of different components, enabling electronics to be located near the generator without compromising temperature control, thus reducing system complexity while maintaining acceptable operating temperatures.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If electronics are placed outside temperature-controlled bays to reduce system complexity, then system design is simplified, but electronics are at risk of overheating

Engineering Contradiction:
Improvesystem design complexityVSAvoidelectronics temperature control
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The cooling system merges the generator cooling and electronics cooling into a single integrated heat exchanger unit with multiple thermally isolated cores. This allows electronics to be positioned outside separate temperature-controlled bays while still providing dedicated thermal management through the second core, thus simplifying system design while preventing overheating.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If a single cooling system is used for both generator and electronics, then system complexity is reduced, but the distinct temperature requirements of each component cannot be met

Engineering Contradiction:
Improvecooling system complexityVSAvoidcomponent temperature requirements
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The heat exchanger is segmented into multiple thermally isolated cores, with each core dedicated to cooling a specific component (generator or electronics). This segmentation enables the system to meet distinct temperature requirements for each component while maintaining a relatively simple integrated structure, avoiding the need for completely separate cooling systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each core of the heat exchanger is designed with local quality tailored to its specific cooling requirement. The first core is optimized for generator cooling while the second core is optimized for electronics cooling, allowing each region of the heat exchanger to provide the appropriate thermal management for its designated component, thus meeting distinct temperature requirements within a unified system.

Inventive Principle:
Principle #3Local quality

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 solution effectively maintains the operating temperature margins for both generators and electronics, allowing them to be located adjacent to each other without exceeding the maximum operating temperatures, thus simplifying system design and ensuring reliable operation in variable aircraft conditions.

Implementation Method 1

cooling circuits 12 and 14, which are arranged in parallel to reject heat produced by sources 16 and 18 to a cooling medium flowing through heat rejection line 20 via heat exchangers 22 and 24

Methodology Applied
Scientific EffectHeat transfer: Convection

Implementation Method 2

Heat exchanger 26 includes a first heat exchanger core 22 and a second heat exchanger core 24 that are thermally-insulated from each other by insulators 28a-c

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3144623B1Heat exchanger and cooling system for generator electronics cooling
Publication Date: 2018.12.12 HAMILTON SUNDSTRAND CORP
  • EP3144623B1 patent drawingFigure 1
  • EP3144623B1 patent drawingFigure 2
  • EP3144623B1 patent drawingFigure 3

AI summary

A system (10) includes a heat exchanger (26), a first heat source (16) disposed along a first circuit (12), and a second heat source (18) disposed along a second circuit (14). The heat exchanger (26) includes a first core (22) defining a first flow path through the heat exchanger (26) and along the first circuit (12) and a second core (24) defining a second flow path through the heat exchanger (26) and along the second circuit (14) that is parallel to the first flow path. The first and second cores (22, 24) define a third flow path extending through the heat exchanger that is configured to be in a heat exchange (26) relationship with the first and second flow paths.