Embedded Engine Electric Machine With Thermal Buffer Cavity
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Solution Overview
Problem
Aircraft propulsion systems face challenges in providing sufficient electrical power to electric fans due to space and weight constraints, as conventional auxiliary generators in gas turbine engines are inadequate.
Innovation Solution
The integration of an electric machine within the gas turbine engine, thermally insulated by a cavity wall and cooled by a dedicated lubrication and cooling system, which includes a buffer cavity and cooling duct to maintain the electric machine within a desired temperature range, allowing it to generate and transmit electrical power effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If auxiliary generators are positioned within the gas turbine engine cowling, then electrical power can be provided, but the power output is insufficient to adequately drive the electric fan
Solution Approach 1:
The patent merges the electric machine with the gas turbine engine by integrating it into the engine structure, specifically positioning it within the engine core area. This consolidation allows the electric machine to utilize the engine's rotational energy directly and access cooling resources, thereby achieving sufficient power output while avoiding the complexity of separate auxiliary generator systems.
Solution Approach 2:
The electric machine is nested within the gas turbine engine structure, with the buffer cavity and cooling system integrated into the existing engine architecture. This nesting approach allows the electric machine to be housed within the engine's internal volume, utilizing available space efficiently and connecting to the engine's rotational and thermal management systems.
2Device complexity
If the electric machine is positioned within the core air flowpath, then it can be integrated into the engine structure, but the high temperature environment will damage the electric machine components
Solution Approach 1:
The patent segments the engine interior into distinct thermal zones by introducing a buffer cavity between the electric machine and the hot core air flowpath. This segmentation creates a thermal barrier that protects the electric machine from high temperatures while maintaining its integration within the engine structure. The buffer cavity acts as an isolated chamber with controlled thermal conditions.
Solution Approach 2:
The buffer cavity serves as an intermediary thermal zone between the hot core air flowpath and the electric machine. This intermediate structure mediates the thermal interaction, allowing the electric machine to remain integrated within the engine while being protected from direct exposure to high temperatures through the buffering effect of the cavity.
3Power
If sufficient energy storage devices are provided to power the electric fan, then the fan can be adequately powered, but the space and weight requirements become prohibitive
Solution Approach 1:
The electric machine serves itself by directly converting the mechanical energy from the engine's rotation into electrical power. This self-service approach eliminates the need for separate energy storage devices, as the system generates its own power on-demand from the engine's operational energy, thereby avoiding the prohibitive weight and space requirements of battery systems.
4Reliability
If the electric machine is thermally insulated from the core air flowpath, then the electric machine is protected from high temperatures, but the integration complexity increases
Solution Approach 1:
The buffer cavity structure serves multiple functions simultaneously: it provides thermal insulation to protect the electric machine, defines a dedicated cooling channel for airflow management, and maintains structural integration within the engine. This multi-functionality reduces the need for separate thermal management components, thereby limiting the increase in overall device complexity.
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 the gas turbine engine to supply adequate electrical power to electric fans, enhancing propulsion efficiency while maintaining the integrity and longevity of the electric machine components.
Implementation Method 1
a cavity wall defining at least in part a buffer cavity, the buffer cavity surrounding at least a portion of the electric machine to thermally insulate the electric machine
Implementation Method 2
cooled by a dedicated lubrication and cooling system, which includes a buffer cavity and cooling duct to maintain the electric machine within a desired temperature range
Data Source
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AI summary
A gas turbine engine includes a compressor section and a turbine section together defining a core air flowpath. Additionally, a rotary component is rotatable with at least a portion of the compressor section and at least a portion of the turbine section. An electric machine is mounted coaxially with the rotary component and positioned at least partially inward of the core air flowpath along a radial direction of the gas turbine engine. A cavity wall defines at least in part a buffer cavity surrounding at least a portion of the electric machine to thermally insulate the electric machine, e.g., from the relatively high temperatures within the core air flowpath.