Reverse-Flow Turbine Electric Machine Layout for Intake-Air Cooling

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Solution Overview

Problem

Existing gas turbine engines with reverse flow configurations face challenges in efficiently integrating auxiliary components like electric machines due to space constraints and heat management, particularly in turboprop engines where the electric machine is located close to high-temperature components.

Innovation Solution

The electric machine is positioned aft of the core turbine engine, coupled to the low-pressure shaft, and integrated with the intake channel to facilitate heat exchange with incoming air, allowing for cooling and tighter packaging, with optional offtake flow paths for enhanced heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the electric machine is located close to high-temperature components to save space, then device complexity is reduced, but thermal stress and heat management become problematic

Engineering Contradiction:
Improvecomponent integrationVSAvoidthermal stress
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an intermediary cooling air flow path that mediates between the electric machine and the high-temperature turbine components. This cooling air, drawn from the intake channel, acts as a thermal buffer that protects the electric machine from excessive heat while maintaining compact integration with the turbine assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the thermal management function from a separate system and integrates it directly into the air flow path of the turbine. By taking out the cooling requirement and incorporating it into the existing intake air flow, the design achieves thermal protection without adding separate cooling systems or increasing overall complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Temperature

If the electric machine is positioned aft of the core turbine engine, then heat management is improved through heat exchange with incoming air, but device complexity increases due to integration requirements

Engineering Contradiction:
Improveheat managementVSAvoidintegration complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into the aft positioning of the electric machine: it serves as both a power-generating component and a heat exchanger. The intake air flow path is combined with the cooling requirement, allowing the same air stream to perform both propulsion support and thermal management functions simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electric machine positioned aft of the core turbine engine serves multiple purposes: generating supplemental power, exchanging heat with incoming air for thermal management, and potentially serving as a weight counterbalance. This multi-functionality reduces the need for separate dedicated systems.

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

3Productivity

If tighter packaging is implemented to increase power density, then productivity is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvepower densityVSAvoidpackaging precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent utilizes the axial dimension of the turbine engine by positioning the electric machine in the aft direction along the engine axis. This dimensional arrangement allows tighter packaging in the radial direction while maintaining adequate thermal management pathways, effectively increasing power density without compromising manufacturing feasibility.

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

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 configuration enables efficient power supplementation and heat management, allowing for higher power density and improved operational flexibility of the electric machine, while minimizing space and thermal stress.

Implementation Method 1

integrated with the intake channel to facilitate heat exchange with incoming air

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

cooling and tighter packaging, with optional offtake flow paths for enhanced heat transfer

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP4417796B1Reverse flow gas turbine engine having electric machine
Publication Date: 2026.03.04 GENERAL ELECTRIC CO
  • EP4417796B1 patent drawingFigure 1
  • EP4417796B1 patent drawingFigure 2
  • EP4417796B1 patent drawingFigure 3

AI summary

An aircraft engine (10) assembly comprising: a gas turbine engine (10) having a high pressure compressor (22), a high pressure turbine (28), a high pressure shaft (34) coupling the high pressure compressor (22) with the high pressure turbine (28), a low pressure turbine, and a low pressure shaft (36) coupled to the low pressure turbine, the high pressure turbine (28) located forward of the high pressure compressor (22), and the low pressure turbine located on a forward end of the gas turbine engine (10); an intake channel (54) of the gas turbine engine (10) configured to receive an incoming flow of air and form an intake flow of air, the intake channel (54) configured to turn the received incoming flow of air from an incoming flow direction to a first axial direction of the gas turbine engine (10), the incoming flow direction reverse of the first axial direction; and an electric machine (74, 74a, 74b) coupled with the low pressure shaft (36) and located on a side of the high pressure compressor (22) opposite of the high pressure turbine (28) and proximate the intake channel (54), the electric machine (74, 74a, 74b) in heat exchange communication with the intake flow of air such that the electric machine (74, 74a, 74b) transfers heat to the incoming flow of air within the intake channel (54) when the electric machine (74, 74a, 74b) is operated.