Dual-Spool Generator With Axially Translatable Stator
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Solution Overview
Problem
Aircraft gas turbine engines with dual-spool power offtake systems increase power conversion hardware and cabling, impacting surge margin and turbine temperature, while maintaining electric start functionality.
Innovation Solution
An aircraft gas turbine engine with an electrical machine arrangement featuring a stator arrangement that is axially translatable relative to two rotors, allowing it to interact with either the LP or HP spool, reducing the need for duplicate power converters and cabling by switching between spools based on operation mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical machines are coupled to each of the HP spool and LP/IP spool for dual-spool power offtake, then engine operability is improved and electric start functionality is retained, but the amount of power conversion hardware and cabling increases
Solution Approach 1:
The patent implements a single stator arrangement that can serve both the HP spool and LP/IP spool by translating axially between two operational positions. This universal design allows the same power conversion hardware to perform multiple functions - generating power from either spool depending on engine operating conditions, thereby eliminating the need for separate dedicated generators for each spool and reducing overall system complexity
Solution Approach 2:
The stator arrangement is designed with dynamic positioning capability, able to translate axially between a first operational position (aligned with HP spool rotor elements) and a second operational position (aligned with LP/IP spool rotor elements). This dynamic reconfiguration allows the system to adapt to different operating modes - using the HP spool for starting or high-power generation when needed, and the LP/IP spool for steady-state power generation, thereby optimizing engine performance while minimizing hardware requirements
2Adaptability or versatility
If electrical machines are coupled to each of the HP spool and LP/IP spool, then electric start functionality is retained, but mass increases due to power conversion hardware duplication
Solution Approach 1:
The patent merges the functions of two separate electrical machines into a single integrated stator arrangement that can interact with both HP and LP/IP rotors. By combining the power conversion hardware into one shared system rather than using two separate machines, the overall mass is significantly reduced while maintaining the ability to perform electric starting and power generation functions
3Productivity
If separate power conversion hardware is provided for HP and LP/IP spools, then each spool can independently generate power, but fault tolerance is reduced due to increased system complexity
Solution Approach 1:
The single stator arrangement serves as a universal power conversion device that can draw power from either the HP spool or LP/IP spool depending on operational requirements. This universal design actually improves fault tolerance because if one spool or its associated rotor elements fail, the system can still generate power using the other spool by translating the stator to the appropriate position, providing built-in redundancy without requiring duplicate power conversion hardware
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 design minimizes power conversion hardware duplication, reduces mass, and enhances fault tolerance by allowing seamless switching between spools without mechanical disconnection, thus improving engine operability and efficiency.
Implementation Method 1
a stator arrangement comprising an array of stator coils arranged around an axis, the axis being coaxial with an axis of rotation of the first rotor and an axis of rotation of the second rotor
Data Source
AI summary
A gas turbine engine includes: first spool including first compressor and first turbine drivingly coupled by first main shaft; second spool including a second compressor and second turbine drivingly coupled by second main shaft; combustion equipment; electrical machine arrangement including: first rotor drivingly coupled to first main shaft and carrying array of rotor elements; second rotor drivingly coupled to second main shaft and carrying array of rotor elements; and stator arrangement including array of stator coils arranged around an axis, axis being coaxial with an axis of rotation of first rotor and an axis of rotation of second rotor. Stator arrangement is axially translatable relative to first and second rotors, between: a first axial position in which array of stator coils interacts with array of rotor elements of first rotor; and a second axial position in which array of stator coils interacts with array of rotor elements of second rotor.