Gas Turbine Startup Control via Flame Temperature Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for controlling gas turbine assemblies during startup phases lack flexibility and accuracy due to fixed schedules based on gas temperature at the outlet of the intermediate turbine, which can lead to flame instabilities, lean blowout phenomena, and increased pollutant emissions, especially under varying ambient and thermal conditions.
Innovation Solution
A method that controls the fuel mass flow-rate to the first combustor based on the flame temperature inside the combustor, using a predetermined schedule (TFL1) adapted to maintain constant flame temperature during startup, calculated from real-time measurements of multiple engine parameters, including gas temperatures, pressures, and rotational speed, to optimize the start-up phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed TAT1 schedule is used for controlling fuel mass flow-rate during start-up, then the control system is simple and easy to implement, but the system lacks flexibility and accuracy to optimize start-up phase under varying ambient temperature and engine thermal state conditions
Solution Approach 1:
The patent transitions from a fixed TAT1 schedule to a dynamic control system that adapts the fuel mass flow-rate based on real-time measurements of ambient temperature and engine thermal state. The control system dynamically adjusts the start-up schedule to match actual operating conditions, making the system both adaptable and implementable through electronic control.
Solution Approach 2:
The patent changes the control parameters from a fixed TAT1-based schedule to a dynamic schedule that incorporates ambient temperature and engine thermal state as varying parameters. This allows the fuel mass flow-rate to be adjusted according to actual operating conditions, improving adaptability while maintaining control simplicity through parameter-based control logic.
2Difficulty of detecting and measuring
If TAT1 parameter is measured far downstream of the first combustor, then the measurement is easy to obtain, but it does not reveal sudden variations of flame temperature inside the combustor leading to flame instabilities and lean blowout phenomena
Solution Approach 1:
The patent implements a feedback control system that uses TAT1 measurements combined with knowledge of ambient temperature and engine thermal state to infer and control the actual flame temperature conditions. The control system continuously adjusts fuel mass flow-rate based on feedback from these measurements to maintain stable combustion and prevent lean blowout.
Solution Approach 2:
The patent uses TAT1 as an intermediary measurement parameter that, when combined with ambient temperature and engine thermal state information, provides indirect but accurate information about flame temperature conditions. This intermediary approach allows measurement at a convenient location while still achieving precise control of combustion stability.
3Reliability
If a predetermined TFL1 schedule is used to maintain constant flame temperature during start-up, then flame instabilities and lean blowout are minimized, but the control system requires real-time measurement and processing of multiple engine parameters
Solution Approach 1:
The control system performs multiple functions using a single integrated control algorithm: it processes ambient temperature measurements, engine thermal state data, and TAT1 measurements, then generates the appropriate fuel mass flow-rate schedule to maintain constant flame temperature. This multi-functional approach achieves reliable combustion control without requiring separate complex control systems for each function.
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 minimizes flame instabilities, reduces lean blowout and pressure pulsations, and optimizes startup performance across varying conditions, while also lowering pollutant emissions during the start-up phase.
Implementation Method 1
a first combustor (4) in which combustion of a mixture of fuel and compressed air arriving from said compressor occurs for producing a flow of hot gasses
Implementation Method 2
a second combustor (7) which is located downstream of said first combustor (4) and in which combustion of a mixture of fuel and hot gasses arriving from said first combustor (4) occurs
Implementation Method 3
a high-pressure intermediate turbine which is interposed between the two combustors for subjecting the flow of hot gasses moving from first to second combustor to a partial expansion that reduces the temperature of the hot gasses
Data Source
Figure 1~4
Figure 2
Figure 5
AI summary
A method for controlling a gas turbine assembly (1), said gas turbine assembly (1) including: a compressor (2) in which compression of the outside air occurs for producing a flow of compressed air; a sequential combustor including a first combustor (4), in which combustion of a mixture of fuel and compressed air arriving from said compressor (2) occurs for producing a flow of hot gasses, and a second combustor (7) which is located downstream of said first combustor (4) and in which combustion of a mixture of fuel and hot gasses arriving from said first combustor (4) occurs; an intermediate turbine (6) in which a partial expansion of the hot gasses arriving from said first combustor (4) occurs. In the second combustor (7) occurs the combustion of the mixture of fuel and hot gasses arriving from said intermediate turbine (6). The method includes, on a start-up transient operating phase of the gas turbine assembly (1), the step of controlling the fuel mass flow-rate supplied to said first (4) and/or said second combustor (7) on the basis of the flame temperature (TFL1) inside the first combustor (4).