Radial Electric Machine for Aircraft Gas Turbine Engine
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Solution Overview
Problem
The increasing size of electric machines in aircraft gas turbine engines due to rising power demands poses challenges in packaging within limited space, with conventional arrangements being heavy, complex, and inefficient, and alternative embedded generators face difficulties in maintenance access and operation in hot environments.
Innovation Solution
Reorienting the electric machine to a radial configuration and coupling it directly or through a reduction gearbox to the radially extending offtake shaft, allowing for a more compact and efficient arrangement with reduced gearing, and utilizing axial or radial flux electric machines to enhance packaging efficiency and power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If electric machines are increased in size to meet rising power demands, then power output is improved, but packaging within limited engine space becomes more difficult
Solution Approach 1:
The patent transitions from conventional axial alignment to radial alignment of the electric machine with the engine shaft. This dimensional reorientation allows the electric machine to be positioned in the radial direction rather than extending axially, effectively utilizing three-dimensional space within the engine assembly and reducing axial length requirements while maintaining power output capacity
2Ease of manufacture
If conventional axial packaging arrangements are used, then ease of installation is maintained, but weight and complexity increase due to required gearing
Solution Approach 1:
The patent extracts and eliminates the intermediate gearing components from the power transmission system. By directly coupling the electric machine to the engine shaft in a radial configuration, the complex gear trains required in conventional axial arrangements are removed, reducing both weight and mechanical complexity while simplifying the installation process
3Volume of moving object
If embedded generators are used within the compressor annular space, then packaging efficiency is improved, but maintenance access becomes difficult and the machine operates in a hot environment
Solution Approach 1:
The patent positions the electric machine in the radial direction extending from the engine shaft, rather than embedding it within the compressor annular space. This radial positioning provides external access to the electric machine for maintenance while still achieving compact packaging within the overall engine envelope, and locates the machine in a cooler environment away from the compressor hot section
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 approach results in a lighter, more compact, and efficient electric machine arrangement that improves packaging efficiency, reduces weight, and increases power density, while providing redundancy and easier maintenance access.
Implementation Method 1
a generator configured to generate electrical power when in a running mode
Implementation Method 2
an electric motor configured to provide motive power to start the gas turbine engine in a starting mode
Data Source
AI summary
An aircraft gas turbine engine (10) comprises a main engine shaft (22) arranged to couple a turbine (17) and a compressor (13), the main engine shaft (22) defining an axial direction (9). The gas turbine engine (10) further comprises at least one radially extending offtake shaft (27) coupled to the main engine shaft (22), and a radially extending electric machine (25a, 25b) coupled to the radially extending offtake shaft (22).