Gas Turbine Motoring Cycle Thermal Stabilization
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Solution Overview
Problem
Gas turbine engines face issues with thermal stabilization during motoring cycles, leading to uneven thermal expansion and component deformation, which can cause rotor blade deflection and tip strikes, resulting in wear and poor reliability in starter air valve systems.
Innovation Solution
A system that modulates airflow to the engine starter by controlling the output pressure of the auxiliary power unit (APU) and starter air valve, using a controller to regulate the rotation speed of the gas turbine engine, thereby uniformly distributing temperature and reducing deformation, and incorporating sensors for feedback to adjust airflow based on engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the starter air valve position is modulated to control airflow to the air turbine starter, then the rotation speed of the gas turbine engine can be controlled, but this causes undesirable wear in the starter air valve and poor system reliability and durability
Solution Approach 1:
The patent introduces a controllable valve positioned between the air turbine starter and the engine air inlet as an intermediary device. This valve modulates airflow to the air turbine starter, enabling precise control of engine rotation speed during the motoring cycle while protecting the main starter air valve from wear by directing controlled airflow through this intermediate valve instead.
2Stability of the object's composition
If thermal stabilization or cooling cycle is performed prior to engine operation, then uniform temperature distribution is achieved, but this increases the time required before engine can be operated
Solution Approach 1:
The patent implements periodic airflow modulation to the air turbine starter during the motoring cycle, creating oscillating thermal conditions that accelerate thermal stabilization. The controller activates the air turbine starter in periodic cycles, causing repeated heating and cooling effects that rapidly equalize temperatures across engine components, reducing the overall thermal stabilization time.
Solution Approach 2:
The patent performs preliminary thermal stabilization by controlling airflow to the air turbine starter before formal engine operation begins. The controller manages the motoring cycle to establish uniform temperature distribution in advance, ensuring engine components are thermally prepared for operation without requiring extended cooling periods afterward.
3Productivity
If the air turbine starter is used for cooling cycle and subsequent spool up to ignition, then the gas turbine engine can be started, but uneven thermal expansion and component deformation occur leading to rotor blade deflection and tip strikes
Solution Approach 1:
The patent implements a feedback control system where sensors monitor temperature distribution and engine parameters during the motoring cycle. The controller receives this feedback and dynamically adjusts airflow to the air turbine starter, modulating the cooling process to maintain uniform thermal expansion across components. This feedback mechanism prevents excessive temperature gradients that would cause rotor blade deflection and tip strikes.
Data Source
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AI summary
Systems and methods for rotating a gas turbine engine (110) during a motoring cycle are provided. The system may comprise a controller (120) in electronic communication with an auxiliary power unit (APU) (130), a starter air valve (140), and a gas turbine engine (110). The APU (130) may supply compressed air to the starter air valve (140) which may supply the compressed air to an engine starter (150) in mechanical communication with the engine (110). The rotational speed of the engine (110) may be controlled by the engine starter (150) based on the pressure of the compressed air received from the starter air valve (140). The controller (120) may be configured to control airflow and air pressure through the system, by modulating the airflow from the APU (130) and/or from the starter air valve (140).