Gas Turbine Combustor Exit Temperature Determination
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Solution Overview
Problem
Conventional methods fail to accurately determine the exit temperature of a gas turbine's combustor during transient operations, leading to potential damage of nozzle guide vanes due to thermal stress, as existing temperature measurement techniques are slow to respond and do not reflect the true combustor exit temperature effectively.
Innovation Solution
A method that determines the combustor exit temperature by calculating the energy balance based on the mass flow and temperature of fuel and air delivered to the combustor, considering the temperature dependence of the specific heat capacity of the burnt mixture, using iterative equations to refine the temperature estimation, and integrating this data over time to control the gas turbine and prevent component damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional temperature measurement techniques are used, then the measurement system is simple, but the response speed is slow and the measurement precision is insufficient during transient operations
Solution Approach 1:
The patent replaces conventional mechanical/physical temperature measurement devices (thermocouples, radiation pyrometers) with a computational model-based determination system. The model calculates combustor exit temperature by integrating measured parameters (fuel flow, air flow, compressor outlet temperature, turbine inlet temperature) through thermodynamic relationships, substituting direct physical measurement with mathematical computation to achieve faster response and higher precision during transient operations.
Solution Approach 2:
The patent introduces a temperature determination device as an intermediary computational layer between the physical measurement sensors and the control system. This intermediary processes multiple measured parameters through a thermodynamic model to derive the combustor exit temperature, acting as a mediator that transforms raw sensor data into accurate temperature information without requiring direct contact with the extreme thermal environment.
2Productivity
If the gas turbine operates at high temperatures to improve efficiency, then the energy conversion efficiency increases, but the thermal stress on nozzle guide vanes increases causing potential damage
Solution Approach 1:
The patent implements a feedback control mechanism where the determined combustor exit temperature continuously feeds back to the control system. This feedback enables real-time monitoring and adjustment of operating parameters to maintain temperatures within optimal ranges for efficiency while preventing excessive thermal stress on components. The control system uses this feedback to modulate fuel and air flow rates, ensuring high efficiency operation without compromising component safety.
Solution Approach 2:
The patent applies preliminary action by determining and monitoring the combustor exit temperature before it reaches levels that could cause damage to nozzle guide vanes. The system proactively identifies approaching thermal limits and adjusts operating parameters in advance to prevent harmful thermal stress, rather than reacting after damage occurs. This predictive approach allows the turbine to operate near efficiency limits while maintaining component safety.
3Power
If the combustor exit temperature is increased to improve power output, then the turbine power increases, but the risk of component failure due to thermal stress increases
Solution Approach 1:
The patent applies dynamics by implementing a dynamic temperature determination and control system that adapts to changing operating conditions in real-time. Rather than using fixed temperature limits, the system continuously calculates the actual combustor exit temperature based on current fuel flow, air flow, and thermodynamic state, enabling the turbine to dynamically operate at optimal power levels while maintaining component reliability. This dynamic approach allows temporary excursions beyond steady-state limits during transient operations without compromising reliability.
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 allows for accurate determination of the combustor exit temperature, enabling more effective control of the gas turbine to prevent component damage, especially during transient operations, by integrating thermal load over time, thus maintaining efficient operation while protecting turbine components from excessive temperatures.
Implementation Method 1
determining a combustor exit temperature of a gas exiting a combustor of the gas turbine, in particular by applying an energy balance
Implementation Method 2
determining a temperature dependence of a specific heat capacity of a burnt mixture of the fuel and the air being delivered to the combustor
Implementation Method 3
the hot combustion gas contacting the nozzle guide vanes and transferring thermal energy to the nozzle guide vanes
Implementation Method 4
leading to potential damage of nozzle guide vanes due to thermal stress
Implementation Method 5
energy contained in the combustion gas in form of pressure and velocity may be converted to mechanical energy
Data Source
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AI summary
It is described a method of determining an exit temperature of a gas exiting a combustor (24) of a gas turbine (10), the method comprising: determining a mass flow and a temperature of fuel being delivered to the combustor; determining a mass flow and a temperature of air being delivered to the combustor; determining a temperature dependence of the specific heat capacity of a burnt mixture of the fuel and the air being delivered to the combustor; and determining an exit temperature of the burnt mixture exiting the combustor based on the determined mass flow and temperature of the fuel, the determined mass flow and temperature of the air, and the determined temperature dependence of the specific heat capacity of the burnt mixture. Further a method of controlling a gas turbine is described.