Aft-Mounted Electric Machine for Hybrid Gas Turbine Servicing

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Solution Overview

Problem

Existing gas turbine engines face challenges in efficiently integrating electric machines due to packaging limitations, which complicate removal, analysis, maintenance, and servicing, particularly in hybrid configurations.

Innovation Solution

A hybrid electric gas turbine engine design with an aft-mounted electric machine assembly that facilitates easy removal, analysis, and maintenance by positioning the electric machine aft of the core air flowpath exhaust, allowing for flexible couplings and seals to accommodate temperature variations and misalignments, and enabling efficient power transfer between the turbomachine and electric machine.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the electric machine is integrated within the core air flowpath structure, then the packaging efficiency is improved, but the ease of removal and maintenance deteriorates

Engineering Contradiction:
Improvepackaging efficiencyVSAvoidease of removal and maintenance
Core Design Contradiction:
Volume of moving objectVSEase of repair

Solution Approach 1:

The propulsion system is divided into separate modules: the gas turbine engine core and the electric machine assembly. The electric machine is positioned in a separate aft location rather than being integrated within the core structure, allowing it to be independently removed and serviced without disassembling the main engine core.

Inventive Principle:
Principle #1Segmentation

2Ease of repair

If the electric machine is positioned aft of the core air flowpath exhaust, then the ease of maintenance is improved, but the device complexity increases due to flexible couplings and seals

Engineering Contradiction:
Improveease of maintenanceVSAvoiddevice complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The coupling mechanism incorporates flexibility to accommodate thermal expansion and misalignment. The seal system is designed to maintain fluid-tight connections while allowing for relative movement and temperature variations between the engine core and electric machine assembly.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If flexible couplings are used to accommodate temperature variations, then the adaptability is improved, but the manufacturing precision requirements worsen

Engineering Contradiction:
Improveadaptability to temperature variationsVSAvoidmanufacturing precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The coupling system is designed with dynamic characteristics that allow it to adapt to changing operating conditions. The flexible coupling accommodates thermal expansion and misalignment through its inherent compliance, reducing the need for extremely tight manufacturing tolerances while maintaining reliable power transfer.

Inventive Principle:
Principle #15Dynamics

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 design allows for seamless integration and servicing of the electric machine, enhancing operational efficiency and ease of maintenance while maintaining fluid-tight seals and accommodating temperature changes, thus improving overall engine performance and reliability.

Implementation Method 1

flexible couplings and seals to accommodate temperature variations

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

flexible couplings and seals to accommodate temperature variations

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4390062B1Hybrid electric gas turbine engine
Publication Date: 2025.09.24 GENERAL ELECTRIC CO
  • EP4390062B1 patent drawingFigure 1
  • EP4390062B1 patent drawingFigure 2
  • EP4390062B1 patent drawingFigure 3

AI summary

A hybrid electric gas turbine engine (10) is provided. The hybrid electric gas turbine engine (10) includes: a turbomachine (16) having a compressor section (22, 24) and a turbine section (28, 30) arranged in serial flow order, the compressor section (22, 24) and turbine section (28, 30) together defining a core air flowpath, the turbomachine (16) defining a core air flowpath exhaust; and an electric machine assembly (200) comprising an electric machine (201) disposed aft of the core air flowpath exhaust and connected to the turbine section (22, 24).