Gas Turbine Control Device Combustion Vibration Management
Solution Overview
Problem
Gas turbines face operational instability due to combustion vibrations, which can lead to equipment damage and increased maintenance costs, as existing control methods often focus on lower frequency bands, potentially worsening vibrations in higher frequency bands and causing unpredictable load fluctuations.
Innovation Solution
A gas turbine control method and device that adjusts fuel and airflow rates based on optimal operation conditions searched using load sensitivity coefficients, while preventing combustion vibrations, to maintain ideal operating conditions and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If combustion vibrations are restrained by adjusting fuel flow rate and airflow rate based on existing control methods, then lower frequency band vibrations are reduced, but higher frequency band vibrations are worsened and load fluctuations become unpredictable
Solution Approach 1:
The patent segments the combustion vibration control into multiple frequency bands (lower frequency band and higher frequency band) and applies different control strategies for each band. The lower frequency band is controlled by traditional fuel flow rate and airflow rate adjustments, while the higher frequency band is controlled by adjusting the pilot fuel flow rate separately, preventing the worsening of vibrations in one band while controlling vibrations in another band.
Solution Approach 2:
The patent applies local quality by differentiating the control approach for different frequency bands. Specifically, the pilot fuel flow rate is adjusted independently to address higher frequency band vibrations, while the main fuel flow rate and airflow rate are adjusted for lower frequency band vibrations. This localized control quality ensures that control actions in one frequency band do not adversely affect another band.
2Manufacturing precision
If trial operations are performed to fine adjust airflow rate and fuel flow rate, then optimal operation conditions are achieved, but the period is limited and cannot cover all weather conditions
Solution Approach 1:
The patent performs preliminary action by conducting trial operations under various weather conditions beforehand to fine-adjust the airflow rate and fuel flow rate. These optimized values are stored as reference data for different weather conditions, allowing the gas turbine to operate optimally without requiring extensive trial operations during actual deployment across all possible weather scenarios.
Solution Approach 2:
The patent implements feedback by storing the results of trial operations (optimized airflow rate and fuel flow rate values) in a database or memory, and using these stored values to automatically adjust operation parameters during actual operation based on detected weather conditions, eliminating the need for repeated trial operations under all possible weather conditions.
3Ease of operation
If the gas turbine operates under irregular conditions deviated from ideal fuel flow rate and airflow rate, then operational flexibility is increased, but combustion vibrations occur and equipment damage risk increases
Solution Approach 1:
The patent applies dynamics by enabling real-time adjustment of operation parameters (fuel flow rate, airflow rate, pilot fuel flow rate) based on detected combustion vibrations and operational conditions. The control system dynamically modifies operation parameters to maintain optimal combustion conditions even when operating conditions change, preventing equipment damage while maintaining operational flexibility.
Solution Approach 2:
The patent implements feedback by continuously monitoring combustion vibrations and operation parameters, comparing them against ideal values, and automatically adjusting fuel flow rate, airflow rate, and pilot fuel flow rate to correct deviations. This closed-loop feedback control ensures that the gas turbine operates under ideal conditions even during load changes or weather variations, preventing equipment damage while maintaining operational flexibility.
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
The method ensures continuous normal operation within ideal fuel and airflow rate conditions, reducing the risk of equipment damage and maintenance costs by effectively managing combustion vibrations across multiple frequency bands and stabilizing load fluctuations.
Implementation Method 1
the gas turbine is driven by the combustion gas produced through the continuous exothermic oxidation reaction between the fuel and the air supplied into the combustors
Implementation Method 2
the combustion occasionally accompanies the combustion gas pressure fluctuations of a frequency from 10-Hz to several thousands-Hz, the combustion gas pressure fluctuations including: the combustion noise caused by the turbulent flow combustion due to the exothermic oxidation reaction, and the combustion vibration caused by the interaction between the heat dissipation due to the time lag from fuel evaporation to fuel combustion and the flame propagation speed change due to combustion gas diffusion and revolution
Data Source
Figure 1(A)~1(B)
Figure 2
Figure 3~4
AI summary
Provided is a gas turbine control method and control device whereby a design performance and an operating state based on ideal fuel flow rate and air flow rate simulated at the time of designing can be maintained by preventing an operation deviated from an operating condition that is based on ideal fuel flow rate and air flow rate simulated by initial design values, in a gas turbine control method designed to search optimal operating conditions automatically using control inputs such as a pilot ratio. The gas turbine controller comprises a second database that stores load sensitivity, i.e. the correlation between the load amount of a gas turbine and control inputs such as a fuel flow rate, air flow rate, pilot fuel ratio, and top hat fuel ratio in the gas turbine, wherein the amount of load variation for at least one of control inputs, a fuel flow rate or an air flow rate supplied to a combustor is predicted according to operational conditions obtained by searching using the load sensitivity, regulation is made according to the prediction results, and the regulation results are stored in the second database.