Electric Compressor Stage Adds Torque for Gas Turbine Start-Up
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Solution Overview
Problem
Air turbine starters for gas turbines take a longer time to start engine operation, while electric starters may not have sufficient torque to initiate large gas turbines effectively.
Innovation Solution
Incorporating an electric compressor stage driven by an electric motor, which can be decoupled or coupled with the low-pressure and high-pressure compressors, allowing for independent operation and providing additional torque for faster engine start-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If an air turbine starter is used to start a gas turbine engine, then sufficient torque can be provided for large engines, but the start-up time becomes longer
Solution Approach 1:
The starter system is segmented into two independent components: an electric starter motor for rapid initial rotation and an air turbine starter for sustained torque provision. This segmentation allows each component to operate optimally within its strengths, with the electric motor providing quick start-up and the air turbine taking over for continued acceleration, thereby reducing overall start-up time while maintaining sufficient torque.
Solution Approach 2:
The electric starter motor performs preliminary action by rapidly accelerating the engine to a predetermined speed before the air turbine starter engages. This preliminary acceleration reduces the workload on the air turbine during the critical initial phase, enabling faster overall start-up while ensuring sufficient torque is available when needed most.
2Loss of time
If an electric starter is used to start a gas turbine engine, then start-up time is reduced, but insufficient torque is available for large engines
Solution Approach 1:
The starter system is divided into two functional segments: an electric starter motor that excels at rapid acceleration and an air turbine starter that provides sustained high torque. The electric motor handles the time-critical initial acceleration phase, while the air turbine takes over for the torque-intensive continuation phase, thus achieving both fast start-up and sufficient torque for large engines.
Solution Approach 2:
A clutch mechanism acts as an intermediary between the electric starter motor and the engine, controlling the engagement and disengagement of the two starter types. This intermediary allows seamless transition from electric to air turbine power, ensuring continuous torque delivery while optimizing start-up time through coordinated operation of both components.
3Force
If a separate electric starter system is added to provide sufficient torque, then torque availability increases, but device complexity increases
Solution Approach 1:
The electric starter motor and air turbine starter are merged into a single integrated starter system with shared mounting structures, control electronics, and drivetrain components. This merging reduces overall system complexity compared to having completely separate systems, while still providing the torque benefits of both components through coordinated operation.
Solution Approach 2:
The clutch mechanism serves multiple functions: it engages/disengages the electric starter motor, engages/disengages the air turbine starter, and can operate in different modes (electric-only, air turbine-only, or combined). This multi-functionality reduces the need for separate control mechanisms for each starter type, thereby reducing overall system complexity while maintaining torque availability.
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 electric compressor stage enhances engine start-up efficiency, reduces weight, and maintains optimal airflow during various flight stages, enabling quicker engine initiation and reducing torque limitations.
Implementation Method 1
an electric motor, where the compressor section includes a low-pressure compressor, a high-pressure compressor, and an electric compressor stage
Data Source
Figure 1
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AI summary
A gas turbine engine (200) includes a compressor section (104), a turbine section (108), a low-speed shaft (110), a high-speed shaft (112), an electric compressor stage shaft (113), and an electric motor (128). The compressor section (104) includes a low-pressure compressor (116), a high-pressure compressor (122), and an electric compressor stage (132). The turbine section (108) includes a low-pressure turbine (118) and a high-pressure turbine (124). The low-speed shaft (110) interconnects the low-pressure compressor (116) and the low-pressure turbine (118). The high-speed shaft (112) interconnects the high-pressure compressor (122) and the high-pressure turbine (124). The electric compressor stage shaft (113) connects to the electric compressor stage (132). The electric motor (128) is configured to drive the electric compressor stage shaft (113).