LP Shaft Generator Torque Control for Turbine Stall Recovery
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Solution Overview
Problem
Gas turbine engine systems face challenges in efficiently managing torque and power generation during deceleration and in responding to stalls or surges, which can lead to reduced performance and increased risk of compressor stall or surge.
Innovation Solution
The system includes a generator coupled to the low-pressure spool shaft, which generates electrical power from the rotation of the shaft and can increase the torque applied to the shaft by adjusting the power generation, particularly during deceleration, stalls, or surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the generator increases power generation to increase torque on the LP shaft, then the torque applied to the second shaft is improved, but the engine thrust is reduced
Solution Approach 1:
The generator's power generation level is dynamically adjusted based on real-time engine operating conditions. During deceleration or surge/stall events, the controller increases the generator's electrical load to provide counter-torque on the LP shaft, preventing compressor instability. During normal operation, the generator operates at optimal power levels to minimize impact on engine thrust while still providing necessary electrical power.
Solution Approach 2:
The system changes the electrical load parameter of the generator to control the torque applied to the LP shaft. By adjusting the electrical power generation level, the generator's electromagnetic torque is varied, which directly influences the LP shaft torque without requiring mechanical modifications to the engine's thrust production system.
2Speed
If the generator applies increased torque to the second shaft during deceleration, then the deceleration rate is improved, but the transient deviation from the working line increases
Solution Approach 1:
The controller continuously monitors engine operating parameters including LP shaft speed, compressor pressure ratios, and generator power output. Based on this feedback, the controller dynamically adjusts the generator's electrical load to provide the precise amount of counter-torque needed to control deceleration rate while maintaining the compressor operating point within acceptable deviation limits from the working line.
Solution Approach 2:
The system dynamically balances two competing requirements during deceleration: applying sufficient torque to achieve desired deceleration rate while limiting torque to prevent excessive transient deviation. The generator's torque output is continuously modulated based on real-time measurements of compressor operating conditions, allowing the system to adaptively optimize the trade-off between deceleration performance and compressor stability.
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 approach improves the operation of the gas turbine engine by allowing for faster deceleration, reduced transient deviations from the working line, and enhanced prevention of compressor stalls or surges, thereby improving overall engine performance and stability.
Implementation Method 1
a generator coupled to the second shaft, wherein the generator is configured to generate electrical power from a rotation of the second shaft
Implementation Method 2
increase the electrical power generated by the generator to increase a torque applied to the second shaft by the generator
Data Source
AI summary
In some examples, a system including a gas turbine engine, the engine including a high-pressure (HP) shaft; HP compressor; HP turbine, second shaft; second compressor; second turbine, the second turbine being coupled to the second compressor via the second shaft (e.g., LP shaft); and a generator coupled to the LP shaft. The generator is configured to generate electrical power from rotation of the LP shaft, and increase electrical power generated by the generator to increase a torque applied to the LP shaft by the generator, e.g., in combination with reduction in engine thrust, or in response to the detection of a stall and/or surge of the engine. The increase in torque applied to the second shaft is configured to increase a rate at which a rotational speed of the second shaft decreases, e.g., in combination with the reduction in engine thrust or during the stall/surge of the engine.