Valve Opening Degree Determination for Gas Turbine Disk Cavity
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Solution Overview
Problem
The challenge in gas turbines is maintaining the temperature of the disk cavity below a certain limit while preventing hot gas inflow, as the pressure balance between cooling air and hot gas can lead to hot gas backflow, causing rapid temperature increases, and excessive cooling air reduces turbine performance.
Innovation Solution
A valve opening degree determination device that uses a prediction model based on previous data to calculate the optimal valve opening for the cooling-air adjustment valve, ensuring the disk cavity temperature remains at or below a target temperature, thereby improving gas turbine performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling air is excessively introduced to the disk cavity to prevent hot gas backflow, then the temperature of the disk cavity is maintained below the temperature limit, but the temperature of the hot gas decreases and the performance of the gas turbine is reduced
Solution Approach 1:
The system performs preliminary determination of the valve opening degree using a prediction model that forecasts disk cavity temperature based on current operating conditions. This allows the cooling air supply to be optimized in advance, preventing hot gas backflow while minimizing the cooling air amount to maintain turbine performance.
Solution Approach 2:
The system uses feedback from actual disk cavity temperature measurements to update and refine the prediction model. The determination unit adjusts the valve opening degree based on both predicted temperature and actual temperature feedback, enabling precise control that prevents overheating without excessive cooling air intake.
2Productivity
If the valve opening degree is precisely controlled to minimize cooling air supply, then gas turbine performance is improved, but the risk of hot gas backflow into the disk cavity increases
Solution Approach 1:
The prediction model performs preliminary assessment of the disk cavity temperature based on current operating conditions and seal member characteristics. This allows the system to determine the optimal valve opening degree in advance that minimizes cooling air supply while ensuring temperature control, thus improving performance without compromising reliability.
Solution Approach 2:
The system dynamically adjusts the valve opening degree parameter based on changing operating conditions and seal member aging characteristics. The prediction model incorporates seal member gap changes due to aging, allowing the valve opening degree to be optimized for each operating state, achieving both performance improvement and reliable temperature control.
3Reliability
If the seal member gap increases due to aging, then the pressure balance changes and hot gas backflow is more likely to occur, but increasing cooling air supply to compensate reduces gas turbine performance
Solution Approach 1:
The system performs preliminary determination of the valve opening degree that accounts for seal member aging characteristics. The prediction model incorporates the relationship between seal member gap and cooling air supply, allowing the system to proactively adjust the valve opening degree to compensate for aging effects without excessive cooling air intake, thus maintaining both reliability and performance.
Solution Approach 2:
The system dynamically changes the valve opening degree parameter based on seal member aging status and operating conditions. By incorporating seal member gap characteristics into the prediction model, the system optimizes the cooling air supply parameter to prevent hot gas backflow due to aging while minimizing the impact on gas turbine performance.
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 solution effectively maintains the disk cavity temperature within limits, preventing hot gas backflow and enhancing gas turbine performance by accurately determining the valve opening degree based on the gas turbine's operating state.
Implementation Method 1
the pressure balance between the hot gas on the gas flow passage side and the cooling air on the cooling passage side, which are opposed across the seal member
Implementation Method 2
the temperature of the disk cavity is kept below a temperature limit
Data Source
AI summary
A valve opening degree determination device includes an object operating state acquisition unit configured to acquire an object operating state which is an operating state of a gas turbine before control, and a valve opening degree calculation unit configured to calculate the valve opening degree such that a disk cavity temperature after control is equal to or lower than a target temperature, based on the object operating state. The valve opening degree calculation unit is configured to determine an input value of the valve opening degree such that a prediction value of the disk cavity temperature is equal to or lower than the target temperature as the valve opening degree, based on a prediction model generated based on a plurality of previous data in which the operating state, the disk cavity temperature, and an actual opening degree of the cooling-air adjustment valve previously acquired are associated with each other.