Aft-Mounted Electric Machine Assembly for Hybrid Gas Turbines
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Solution Overview
Problem
Existing gas turbine engines face challenges in efficiently integrating electric machines due to packaging constraints, which complicate removal, analysis, and maintenance of these components.
Innovation Solution
A hybrid electric gas turbine engine design positions the electric machine aft of the core air flowpath exhaust, allowing for easy removal and maintenance, and incorporates flexible couplings and seals to accommodate temperature and alignment variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the electric machine is integrated within the core gas turbine engine structure, then the engine achieves compact packaging, but the electric machine becomes difficult to remove, analyze, and maintain
Solution Approach 1:
The electric machine assembly is segmented as a separate, modular unit that can be independently removed from the gas turbine engine. The assembly housing defines a discrete volume that can be detached as a complete unit, allowing the electric machine to be separated from the core engine structure for maintenance while maintaining compact integration during operation.
Solution Approach 2:
The electric machine assembly is extracted from the core gas turbine engine structure and positioned in a dedicated aft location. The assembly housing couples to the engine case but can be removed as a separate unit, enabling the electric machine to be taken out for maintenance without disassembling the core engine components.
2Power
If the electric machine is positioned close to the turbine section for mechanical connection, then torque transfer is efficient, but the electric machine is exposed to high temperature and alignment variations
Solution Approach 1:
A flexible coupling is introduced as an intermediary element between the turbine section and the electric machine assembly. This coupling accommodates thermal expansion and alignment variations while maintaining efficient torque transfer, protecting the electric machine from direct exposure to high temperature and mechanical stress.
Solution Approach 2:
The flexible coupling uses flexible mechanical elements to connect the turbine shaft to the electric machine input shaft. This flexible connection allows for relative movement and misalignment accommodation due to thermal expansion, while still transmitting torque efficiently to the electric machine.
3Stability of the object's composition
If the electric machine assembly housing is rigidly coupled to the engine case, then structural stability is maximized, but temperature and alignment variations cause mechanical stress
Solution Approach 1:
The coupling between the assembly housing and engine case transitions from a rigid, fixed connection to a dynamic, flexible connection. The flexible coupling allows the electric machine assembly to move relative to the engine case in response to thermal expansion and alignment variations, reducing mechanical stress while maintaining structural stability.
Data Source
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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).