Hybrid Spool Starting for Faster Gas Turbine Engine Relight
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Solution Overview
Problem
Gas turbine engines face challenges in achieving faster and more reliable startups, particularly in cold start conditions and relight situations, with existing starting systems being time-consuming and prone to reliability issues.
Innovation Solution
A hybrid electric configuration is introduced, incorporating an electric motor coupled to the low-speed spool for propulsive power and an accessory gearbox and starter motor coupled to the high-speed spool, with a clutch to interconnect both spools, reducing inertial lag and enabling quicker and more reliable engine startups and relights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional starting system is used for gas turbine engine startup, then the system structure is relatively simple, but the startup time is long and reliability is reduced
Solution Approach 1:
The patent combines a traditional starter motor with an electric motor into a hybrid starting system. The electric motor is coupled to the low-speed spool while the starter motor remains coupled to the high-speed spool, creating a dual-path starting mechanism that improves reliability by providing redundant starting capabilities and reducing inertial lag during startup.
2Speed
If a traditional starting system is used for gas turbine engine startup, then the system complexity is lower, but the startup speed is slower due to inertial lag
Solution Approach 1:
The starting system is segmented into two independent paths: one through the high-speed spool (traditional starter motor) and another through the low-speed spool (electric motor). This segmentation allows each motor to independently contribute to the startup process, reducing overall inertial lag and enabling faster engine acceleration.
3Reliability
If existing starting systems are used in cold start conditions, then the system structure remains simple, but the startup reliability is reduced
Solution Approach 1:
The hybrid starting system provides dynamic adaptability for different operating conditions. The control system can selectively engage the electric motor, starter motor, or both simultaneously depending on ambient temperature and engine conditions, optimizing startup reliability for cold conditions while maintaining system simplicity through intelligent control strategies.
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
The hybrid electric configuration facilitates faster and more reliable engine startups and relights, expanding the relight envelope and providing redundant systems for improved engine operation.
Implementation Method 1
an electric motor coupled to a low-speed spool for providing propulsive power
Implementation Method 2
an accessory gearbox and starter motor coupled to a high-speed spool
Implementation Method 3
a clutch to interconnect both spools, reducing inertial lag
Implementation Method 4
A combustion section receives pressurized air, which is mixed with fuel and combusted within a combustion chamber to generate combustion gases
Implementation Method 5
The combustion gases are provided first to a high-speed turbine of the high-speed spool, driving the high-speed spool
Implementation Method 6
subsequently to a low-speed turbine of the low-speed spool, driving the low-speed spool
Data Source
AI summary
A gas turbine engine includes a turbomachine comprising a low pressure (LP) spool and a high pressure (HP) spool that rotate about a central axis, an electric motor mechanically coupled to the LP spool for selectively rotating the LP spool, a starter assembly mechanically coupled to the HP spool for selectively rotating the HP spool, and a controller in operative communication with the electric motor and the starter assembly, the controller being configured to operate the electric motor to rotate the LP spool and operate the starter assembly to rotate the HP spool during engine startup.