Exhaust Chamber Cooling Control for Steam Turbine Blade Protection
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Solution Overview
Problem
In steam turbine power generating facilities, operating in extremely low load regions leads to increased temperatures in the exhaust chamber and blade tips, causing heat generation and erosion, which shortens blade lifetime and requires continuous exhaust chamber spray water operation, but this is inefficient and causes blade erosion.
Innovation Solution
An exhaust chamber cooling apparatus that measures generator output, exhaust chamber temperature, and condenser pressure to control the supply of cooling fluid, operating the exhaust chamber spray water only when necessary to prevent excessive temperature and erosion, such as when the condenser pressure is high, and avoiding operation when it is low to minimize spray water usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If exhaust chamber spray water is operated continuously in extremely low load region, then temperature increase of blades is suppressed, but blade erosion occurs and operation efficiency decreases
Solution Approach 1:
The spray water operation is changed from continuous to periodic/pulsed operation. The control device operates the spray water only when specific conditions are met (low load region and high exhaust chamber temperature), rather than continuously. This periodic operation reduces blade erosion while maintaining temperature suppression effectiveness.
Solution Approach 2:
The operation parameters of spray water are changed based on real-time monitoring of load and temperature. The control device adjusts spray water operation dynamically by comparing current load and temperature against predetermined thresholds, optimizing the balance between temperature control and erosion prevention.
2Temperature
If exhaust chamber spray water is operated continuously, then blade temperature is controlled, but energy efficiency deteriorates due to unnecessary water circulation
Solution Approach 1:
The spray water system operates periodically rather than continuously, activating only when the control device detects both low load conditions and high exhaust chamber temperature. This eliminates energy waste from unnecessary water circulation while maintaining effective temperature control when needed.
Solution Approach 2:
The control device implements feedback control by continuously monitoring load and exhaust chamber temperature, and adjusting spray water operation accordingly. This closed-loop control ensures spray water is operated only when actually needed for temperature control, optimizing energy efficiency.
3Duration of action of stationary object
If exhaust chamber spray water operation is restricted to reduce erosion, then blade lifetime is prolonged, but temperature control capability is reduced
Solution Approach 1:
The control device dynamically adjusts spray water operation parameters based on real-time temperature and load conditions. By setting appropriate threshold values for load and temperature, the system ensures spray water operates sufficiently to control temperature while minimizing unnecessary operation that causes erosion, thus extending blade lifetime.
Solution Approach 2:
The spray water system serves itself through automatic control based on sensor feedback. The control device autonomously determines when spray water operation is needed by monitoring temperature and load, eliminating the need for continuous operation while ensuring adequate temperature control when required.
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 effectively suppresses exhaust chamber and blade tip temperatures, prolongs blade lifetime by reducing spray water operation time, and optimizes energy use by aligning spray water operation with condenser pressure conditions.
Implementation Method 1
a part of the water cooled by the cooling system is given pressure by a pump and fed to the exhaust chamber spray 6 in the exhaust chamber R from piping having the actuation valve 5 to be released in the exhaust chamber R as spray
Implementation Method 2
The exhaust chamber cooling apparatus 7...measures generator output, exhaust chamber temperature, and condenser pressure to control the supply of cooling fluid
Data Source
AI summary
In one embodiment, an exhaust chamber cooling apparatus measures output of a generator driven by a steam turbine, a temperature in an exhaust chamber of the turbine, and a pressure in a condenser that changes steam from the turbine back to water. The apparatus further outputs a first signal when it is detected that a measurement value of the output is larger than a first setting value and a measurement value of the temperature is larger than a second setting value, and a second signal when it is detected that the measurement value of the output is smaller than the first setting value and a measurement value of the pressure or a calculation value obtained from the measurement value of the pressure is larger than a third setting value. The apparatus further controls supply of a cooling fluid into the chamber, based on the first or second signal.