Multi-tube Combustor Nozzle Groups for Vibration Control
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Solution Overview
Problem
Existing gas turbines experience vibration issues during the ramp-up process due to non-uniform fuel-air mixture combustion, which affects power generation efficiency and NOx levels.
Innovation Solution
A multi-tube combustor design with multiple fuel nozzle groups of varying diameters and lengths, arranged in concentric annular formations, allows for adjustable fuel-air mixing ratios to match load conditions and stabilize combustion, reducing vibrations and NOx fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single fuel nozzle configuration is used to achieve uniform fuel-air mixing, then mixing uniformity is improved, but vibration occurs during the ramp-up process
Solution Approach 1:
The fuel nozzle system is segmented into multiple groups (first, second, and third groups) with different configurations. Each group has nozzles with different diameters and spray patterns, allowing the system to divide the fuel injection function into separate controllable segments that can be activated based on operational conditions.
Solution Approach 2:
The system dynamically switches between different fuel nozzle groups based on the combustion load condition and ramp-up process stage. The control unit activates specific nozzle groups to match the current operational state, making the fuel injection system adaptable and dynamic rather than static.
2Adaptability or versatility
If fuel nozzles with different diameters are used to adjust mixing ratios, then adaptability to load conditions is improved, but device complexity increases
Solution Approach 1:
Different regions of the combustor are served by fuel nozzles with locally optimized characteristics. The first group has nozzles with larger diameters for high-load conditions, while the third group has nozzles with smaller diameters for low-load conditions. Each location has fuel nozzles tailored to its specific operational requirements.
Solution Approach 2:
The system changes key parameters of the fuel injection system by switching between nozzle groups with different diameters, spray angles, and flow rates. This allows the mixing ratio and fuel injection characteristics to be adjusted according to the combustion load condition without redesigning the entire system.
3Power
If all fuel nozzles operate simultaneously to meet high combustion load, then power output is improved, but combustion vibration and NOx levels increase
Solution Approach 1:
The system uses only the necessary portion of the fuel nozzle groups required for the current load condition. During low-load operation, only the third group with smaller nozzles is activated, avoiding the excessive action of all nozzles firing simultaneously, which reduces combustion vibration and NOx emissions while still meeting the power demand.
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 multi-tube combustor design stabilizes flame generation, reduces combustion vibrations, and improves power generation efficiency by actively managing fuel-air mixing and NOx levels during the ramp-up process.
Implementation Method 1
The fuel and the compressed air are mixed inside the plurality of fuel nozzles
Implementation Method 2
a liner coupled to the nozzle casing and defining a combustion chamber in which a mixture of fuel ejected from the nozzle casing and the compressed air is combusted
Data Source
AI summary
A multi-tube combustor is provided. The multi-tube combustor includes a plurality of fuel nozzles disposed in a nozzle tube provided inside a nozzle casing, each fuel nozzle having a cavity, a plurality of compressed air supply tubes connected to the plurality of fuel nozzles and configured to supply a compressed air to the plurality of fuel nozzles, and an on/off valve provided on the plurality of compressed air supply tubes to open and close the compressed air supply tubes. The fuel and the compressed air are mixed inside the plurality of fuel nozzles, and the plurality of fuel nozzles are divided into a plurality of fuel nozzle groups, and a mixture of the fuel and the compressed air is ejected from one or more selected fuel nozzle groups of the plurality of fuel nozzle groups according to a combustion load condition or during a ramp-up process.