Gas Turbine Engine Startup Control via Phase Segmentation
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Solution Overview
Problem
Inflight restarts of gas turbine engines are complex due to various parameters affecting the outcome, and existing starting methods trade off between weight savings, simplicity, and reliability, with challenges in propagating flames around the combustor for complete ignition.
Innovation Solution
A method and system that modulate engine control parameters in sequential phases to achieve light-up, light-around, and complete ignition, using a processing unit and computer-readable medium to adjust fuel flow, variable geometry mechanisms, and ignition frequency based on operating parameters like altitude and engine speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional starting methods are used to rotate the compressor to sufficient speed, then the engine can achieve light-up, but the complexity of controlling flame propagation around the combustor increases and reliability decreases
Solution Approach 1:
The starting procedure is divided into three distinct phases (light-up, light-around, and complete ignition), with different control parameter sets applied to each phase. This segmentation allows optimized control for each specific objective, improving overall reliability while maintaining manageable complexity through structured progression.
Solution Approach 2:
The system dynamically adjusts engine control parameters based on the current phase of startup and real-time engine conditions. The control parameters are modified sequentially through three phases, allowing the system to adapt to changing conditions during flame propagation, thereby improving reliability without requiring overly complex static control mechanisms.
2Reliability
If multiple engine control parameters are modified simultaneously to ensure complete ignition, then reliability improves, but the control system complexity and difficulty of operation increase
Solution Approach 1:
Control parameters are segmented into three distinct sets corresponding to three phases of startup. Each set is optimized for its specific phase objective, allowing the operator or control system to focus on one phase at a time. This reduces operational complexity while ensuring reliable flame propagation through phase-appropriate parameter control.
Solution Approach 2:
The system prepares and modifies control parameters in advance for each phase before execution. By pre-defining the three phases and their associated parameter sets, the system eliminates the need for complex real-time decision-making during operation, thereby improving ease of operation while maintaining reliability through predetermined optimized control strategies.
3Ease of operation
If a simplified starting procedure is used to reduce operational complexity, then ease of operation improves, but the ability to ensure complete flame propagation around the combustor deteriorates
Solution Approach 1:
The procedure is segmented into three clear phases with distinct control parameter sets, making it simple to follow and execute while ensuring complete flame propagation. Each phase builds upon the previous one, providing a straightforward progression that maintains reliability without requiring complex simultaneous control of multiple parameters.
Solution Approach 2:
The system achieves reliable complete ignition by systematically changing control parameters through three defined phases. Each phase modifies specific parameters appropriate to that stage of flame propagation, providing a simple yet effective methodology that ensures completeness of ignition without requiring complex multi-parameter simultaneous adjustment.
4Productivity
If traditional single-phase starting control is used, then the control system remains simple, but the efficiency and speed of achieving complete ignition decrease
Solution Approach 1:
The startup process is segmented into three phases with optimized control parameters for each, enabling faster and more efficient achievement of complete ignition. The segmentation allows parallel optimization of different control aspects without requiring complex integrated control, thereby improving productivity while managing complexity through structured phase separation.
Solution Approach 2:
The control system dynamically transitions through three phases with different parameter sets, allowing rapid adaptation to the changing conditions during startup. This dynamic approach accelerates the ignition process by applying the most appropriate parameters at each stage, improving productivity without requiring overly complex static control mechanisms.
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
Enhances the reliability and efficiency of gas turbine engine startups by ensuring consistent flame propagation and complete ignition, even in inflight conditions, while minimizing the risk of compressor stall and optimizing fuel usage.
Implementation Method 1
modifying a first set of engine control parameters to cause light-up; in a second phase of the startup, modifying a second set of engine control parameters to set conditions for light-around; and in a third phase of the startup, modifying a third set of engine control parameters to propagate a flame around a combustor
Data Source
AI summary
Methods and systems for starting an aircraft gas turbine engine are described. The method comprises, in a first phase of a startup upon receipt of a start request, modifying a first set of engine control parameters to cause light-up; in a second phase of the startup, modifying a second set of engine control parameters to set conditions for light-around; and in a third phase of the startup, modifying a third set of engine control parameters to propagate a flame around a combustor of the gas turbine engine.