Power Gearbox Casing Heat Exchange Using Embedded Airflow Cooling

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Solution Overview

Problem

The thermal management of power gearboxes in turbo engines is inefficient, leading to space constraints and overheating issues, as existing solutions require external heat exchangers or large bypass-duct space for heat exchange systems.

Innovation Solution

A power gearbox with an integrated heat exchange system featuring an enclosed or embedded heat transfer device, utilizing airflow from the aircraft engine to cool or heat the gearbox, with enhanced heat transfer through ribbed, finned, or studded surfaces, and potentially porous media, allowing for reduced space requirements and dual operational modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If external heat exchangers are used for thermal management of the power gear box, then heat exchange capability is improved, but space requirements increase

Engineering Contradiction:
Improvethermal management capabilityVSAvoidspace requirements
Core Design Contradiction:
TemperatureVSArea of stationary object

Solution Approach 1:

The heat transfer device is integrated into the power gear box casing, merging the heat exchange function with the structural housing. This eliminates the need for separate external heat exchangers while maintaining effective thermal management capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat transfer device is enclosed or embedded within the casing of the power gear box, nesting the thermal management component inside the existing structure. This allows the heat exchange system to occupy space already allocated for the gear box rather than requiring additional external space.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Temperature

If large bypass-duct space is allocated for heat exchange systems, then heat transfer efficiency is improved, but available engine space is reduced

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidbypass-duct space
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

The heat transfer device is combined with the power gear box casing, allowing heat exchange to occur within the gear box volume rather than requiring dedicated bypass-duct space. This integration maintains thermal management effectiveness while preserving engine compartment space.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat transfer device utilizes the three-dimensional space within the gear box casing through embedded or enclosed configurations. This approach transforms the thermal management solution from a two-dimensional surface-mounted external heat exchanger to a volumetric integration within the gear box structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Temperature

If heat transfer area is increased through external heat exchangers, then heat exchange capability is improved, but device complexity increases

Engineering Contradiction:
Improveheat exchange capabilityVSAvoidsystem complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The heat transfer device is merged with the power gear box casing, combining the structural housing and thermal management functions into a single integrated component. This reduces the number of separate parts and simplifies the overall system architecture.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The casing serves dual functions: providing structural enclosure for the power gear box and acting as a heat transfer surface for thermal management. This multi-functionality eliminates the need for dedicated external heat exchanger components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 reduces space needs for heat exchangers, enhances heat transfer efficiency, and allows for both cooling and heating of the power gearbox, utilizing airflow from the engine to manage thermal loads effectively, thereby optimizing thermal management within the aircraft engine.

Implementation Method 1

At least one airflow is directed to the at least one heat transfer device for thermally controlling the power gear box

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

the heat transfer device is enclosed and/or embedded with the casing of the power gear box

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The heat transfer is further enhanced by at least one heat transfer and/or flow guiding structure, in particular a ribbed surface, a finned surface and/or a studded surface

Methodology Applied
Scientific EffectHeat transfer enhancement: Heat Exchanger

Implementation Method 4

oil drops which are centrifugally accelerated within the power gear box can impinge and/or can be directed on or to a hot side of the heat transfer device

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3181834B1Heat exchange system for a power gear box, a power gear box and a turbo engine with a power gear box
Publication Date: 2022.09.07 ROLLS ROYCE DEUT LTD & CO KG
  • EP3181834B1 patent drawingFigure 1
  • EP3181834B1 patent drawingFigure 2
  • EP3181834B1 patent drawingFigure 2A

AI summary

The invention relates to a heat exchange system for a power gear box (10) mechanically coupling at least one low pressure compressor stage with at least one turbine stage in a turbo engine, in particular an aircraft turbo engine (100), wherein at least one heat transfer device (1) is enclosed, embedded and / or attached with the casing (11) of the power gear box (10) and the casing (11) and / or the heat transfer device (1) comprise at least one heat transfer and / or fluid flow guiding structure (5), in particular a ribbed surface, a finned surface and / or a studded surface. It further relates to a power gear box (10) and a turbo engine with a power gear box (10).