Gas Turbine Stall Margin Management via Dynamic Load Control
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Solution Overview
Problem
Gas turbine engines face challenges in achieving stable airflow and maximizing thrust production due to high power extraction for electrical generation, leading to slow acceleration and decreased thrust, necessitating a method to improve performance while maintaining desired electrical power generation.
Innovation Solution
A power management system that controls loads on the starter-electric generator to reduce electrical power draw, supplemented by an auxiliary power supply, ensuring desired engine performance by distributing power from both the starter-electric generator and auxiliary sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high power extraction is used from the gas turbine engine for electrical generation, then electrical power generation is improved, but acceleration speed and thrust production deteriorate
Solution Approach 1:
The patent implements dynamic load management on the starter-electric generator based on real-time engine operating conditions. The controller adjusts the electrical load dynamically - reducing it during acceleration phases to improve stall margin and acceleration performance, while allowing higher loads during steady-state operation to maximize electrical power generation. This dynamic adjustment resolves the contradiction between power extraction and acceleration speed.
Solution Approach 2:
The system changes the operational parameters of the starter-electric generator based on engine state. By monitoring parameters such as rotor speed, compressor pressure ratio, and stall margin, the controller adjusts the electrical power extraction level. This parameter-based control allows the system to optimize between electrical power generation and acceleration performance by adapting the power extraction level to current operating conditions.
2Power
If high power extraction is used from the gas turbine engine for electrical generation, then electrical power generation is improved, but thrust production deteriorates
Solution Approach 1:
The controller dynamically adjusts the electrical load on the starter-electric generator based on desired thrust levels and engine operating conditions. During phases requiring high thrust, the electrical load is reduced to maintain adequate stall margin and compressor airflow. During steady-state operation with sufficient thrust margin, the electrical load is increased to maximize power generation. This dynamic load management resolves the contradiction between electrical power generation and thrust production.
Solution Approach 2:
The system employs feedback control by continuously monitoring engine parameters including compressor inlet flow, rotor speed, and calculated stall margin. Based on this feedback, the controller adjusts the electrical load on the starter-electric generator to maintain optimal operating conditions. This feedback mechanism ensures that thrust production requirements are met while maximizing electrical power generation capability.
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 increases the stall margin, allowing for faster acceleration and increased thrust production by reducing electrical power extraction from the starter-electric generator, thereby enhancing engine efficiency and performance.
Implementation Method 1
The starter-electrical generator extracts mechanical work from the HP shaft and transforms such work into electrical power
Data Source
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AI summary
A method 300 for operating a gas turbine engine having a starter-electric generator (108) driven by one of a plurality of shafts of the gas turbine engine is provided. The method includes determining 302 a desired amount of thrust to be produced by the gas turbine engine, as well as a desired amount of electrical power 304 to be drawn from the starter-electric generator (108) of the gas turbine engine. The method operates the gas turbine engine to produce 306 the desired amount of thrust, while drawing 308 less than the desired amount of electrical power from the starter-electric generator (108). Drawing less than the desired amount of electrical power from the starter-electric generator (108) allows for the desired amount of thrust production, allows for the desired amount of thrust production more quickly, or allows for maintenance of a stall margin for any purpose (such as to increase an efficiency of the engine or to allow for certain engine designs).