Adaptive Fuel Schedule for Gas Turbine Flameout Prevention
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Solution Overview
Problem
Gas turbine engines face challenges in starting efficiently across varying conditions such as altitude and temperature, leading to issues like compressor stall, over temperature, and flameout, as a single fuel and acceleration schedule cannot be used universally.
Innovation Solution
A method and system for controlling fuel flow during engine start, involving a first fuel schedule with a minimum fuel flow limit for light-off, monitoring engine parameters, detecting flameout, and adjusting the fuel schedule by increasing the fuel flow limit to prevent flameout, using a processing unit and computer-readable memory to implement the fuel injection adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single fuel schedule is used for all engine starting conditions, then the device complexity is reduced, but the reliability of engine start deteriorates due to flameout, compressor stall, or over temperature under varying conditions
Solution Approach 1:
The fuel schedule is made dynamic and adaptive rather than static. The system continuously monitors engine parameters (N2 speed, exhaust temperature, fuel flow rate) and adjusts the fuel schedule in real-time based on detected conditions such as flameout, compressor stall, or over temperature, allowing the same fuel control system to handle diverse starting conditions reliably
Solution Approach 2:
The system implements feedback control by monitoring engine operating parameters during start and using this information to adjust the fuel schedule. Sensors detect conditions like flameout (through exhaust temperature and fuel flow monitoring) and compressor stall (through N2 speed monitoring), and the fuel control system responds by modifying fuel flow rates according to pre-defined alternative schedules
2Reliability
If fuel flow is increased to prevent flameout, then the reliability of engine start improves, but the risk of over temperature and compressor stall increases
Solution Approach 1:
The system changes multiple parameters simultaneously and coordinates them: fuel flow rate, accelerator pump duty cycle, and monitor interval are adjusted together based on the detected condition. For example, during flameout detection, the system increases fuel flow rate and accelerator pump duty cycle while extending monitor intervals, creating a coordinated response that prevents flameout without causing over temperature
Solution Approach 2:
The fuel schedule dynamically adapts to current engine conditions rather than applying fixed fuel rates. The system selects from multiple alternative fuel schedules (first through fourth schedules) depending on the detected condition, allowing optimal fuel flow rates that prevent flameout while avoiding over temperature and compressor stall for each specific scenario
3Temperature
If fuel flow is restricted to avoid over temperature, then the risk of over temperature is reduced, but flameout occurs more frequently during start
Solution Approach 1:
The system uses parameter changes to coordinate fuel flow with combustion phase. During light-off phase, higher fuel flow rates are used to ensure reliable ignition. After light-off is confirmed (through exhaust temperature monitoring), the system transitions to lower fuel flow rates to control combustor temperature, preventing over temperature while maintaining light-off reliability through the initial higher fuel delivery
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 solution ensures stable engine start and operation by preventing flameout and maintaining efficient performance across different conditions, allowing for continuous fuel injection and self-sustained engine acceleration.
Implementation Method 1
causing fuel to be injected into a combustor of the engine according to a first fuel schedule
Implementation Method 2
monitoring, following light-off of the engine, at least one operating parameter of the engine, detecting, based on the at least one operating parameter, occurrence of flameout in the engine
Implementation Method 3
increasing the minimum fuel flow limit from the initial value to a first value to obtain an adjusted fuel schedule
Data Source
AI summary
Systems and methods for controlling fuel flow to an engine during start are provided. Fuel is caused to be injected into a combustor of the engine according to a first fuel schedule defining a minimum fuel flow limit required to achieve light-off of the engine, the minimum fuel flow limit set at an initial value. Following light-off of the engine, at least one operating parameter of the engine is monitored. Based on the at least one operating parameter, occurrence of flameout in the engine is detected. In response to detecting occurrence of flameout in the engine, the minimum fuel flow limit is increased from the initial value to a first value to obtain an adjusted fuel schedule, and fuel is caused to be injected into the combustor according to the adjusted fuel schedule.