Aircraft Turbine Electrical Machine Stator Cooling via Primary Gas Flow
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Solution Overview
Problem
The integration of a high-powered electrical machine into a turbine engine is complex due to temperature limitations and cooling challenges, particularly in high-bypass ratio architectures, where traditional oil cooling methods risk pollution and inefficiency.
Innovation Solution
The design incorporates an electrical machine with a rotor driven by the low-pressure body's rotor and a stator cooled by a primary gas flow, surrounded by annular shrouds that optimize temperature management and prevent oil pollution, allowing for efficient heat dissipation and extended machine lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If oil cooling is used for the electrical machine stator, then cooling efficiency is improved, but risk of oil pollution and machine component contamination increases
Solution Approach 1:
The patent extracts the electrical machine from the oil-filled environment by placing it in a separate compartment accessible only by the primary gas flow. This separation eliminates the harmful interaction between oil and machine components while maintaining effective cooling through direct gas flow contact with the stator.
Solution Approach 2:
The patent introduces the primary gas flow as an intermediary cooling medium between the heat-generating stator and the environment. This mediator provides efficient heat removal without the contamination risks associated with oil, leveraging the existing high-temperature gas flow already present in the turbine engine.
2Device complexity
If electrical machine is placed in high-temperature turbine engine environment, then integration is simplified, but machine component temperature exceeds acceptable limits
Solution Approach 1:
The patent segments the turbine engine into distinct thermal zones: a high-temperature region for the gas generator and a controlled lower-temperature zone for the electrical machine. This segmentation allows the machine to operate in a thermally suitable environment while maintaining integration within the overall engine structure.
Solution Approach 2:
The primary gas flow acts as a thermal mediator, providing controlled cooling to the stator. By directing this flow through the machine housing and over the stator surface, the system maintains machine temperatures within acceptable limits while utilizing the existing thermal resources of the turbine engine.
3Adaptability or versatility
If electrical machine is integrated into turbine engine, then hybrid propulsion capability is improved, but cooling system complexity and oil leak management difficulty increase
Solution Approach 1:
The patent makes the primary gas flow serve multiple functions: it provides combustion gases for the gas generator, drives the turbine, and simultaneously cools the electrical machine stator. This multi-functionality eliminates the need for separate cooling systems, reducing overall complexity while enabling hybrid propulsion capabilities.
Solution Approach 2:
The electrical machine cooling system is designed to be self-servicing by utilizing the primary gas flow that already exists in the turbine engine for other purposes. The machine housing and flow ducts are configured to automatically direct the cooling flow where needed without requiring additional active cooling components or complex control systems.
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 optimal temperature conditions for the electrical machine, enhances its service life through primary flow cooling, and avoids oil-related pollution risks, supporting higher power capacities and improved efficiency.
Implementation Method 1
the first annular shroud being configured to cool the by conduction stator as a result of its sweep by the primary flow
Data Source
AI summary
An aircraft turbine engine includes a gas generator and a fan arranged upstream from the gas generator and configured to generate a main gas flow, one portion of which flows in a flow path of the gas generator to form a primary flow, and another portion of which flows in a flow path around the gas generator to form a secondary flow. The gas generator includes a low-pressure compressor that includes a rotor driving the fan. The turbine engine further includes an electric machine. The electric machine includes a rotor rotated by the rotor of the low-pressure compressor, and a stator extending around the rotor of the electric machine and configured to be cooled by the primary flow.