Orifice Plate Fuel Split for Combustion Modal Coupling
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Solution Overview
Problem
Gas turbine systems face challenges in controlling combustion dynamics and modal coupling, which can lead to unwanted sympathetic vibratory responses in components due to coherent combustion dynamics frequencies matching natural frequencies of turbine system components.
Innovation Solution
The implementation of orifice plates in the fuel paths of gas turbine combustors to vary fuel split and combustion dynamics frequencies, reducing modal coupling by altering the geometry and configuration of orifice plates across multiple combustors to disrupt coherent behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If combustion dynamics are allowed to occur at multiple discrete frequencies with coherent relationships between combustors, then combustion efficiency and power output are improved, but modal coupling increases causing unwanted sympathetic vibratory responses in turbine components
Solution Approach 1:
The patent applies local quality by introducing orifice plates with specific geometries (different hole patterns, diameters, or configurations) in the fuel paths of individual combustors. This creates locally differentiated flow characteristics that alter combustion dynamics frequencies in each combustor, reducing modal coupling while maintaining overall system power output.
Solution Approach 2:
The patent changes physical parameters of the fuel delivery system by incorporating orifice plates with controlled hole geometries. These parameter changes (orifice diameter, hole pattern, total flow area) modify the fuel flow rate and mixing characteristics, thereby shifting combustion dynamics frequencies away from coherent relationships that cause vibratory responses.
2Object-affected harmful factors
If orifice plates are added to fuel paths to reduce modal coupling, then vibratory responses are reduced, but device complexity increases
Solution Approach 1:
The orifice plate serves as an intermediary component inserted in the fuel path between the fuel supply and the combustor. This simple intermediary device modifies the fuel flow characteristics without requiring complex control systems, sensors, or active adjustment mechanisms, thereby reducing vibratory responses while adding minimal complexity.
Solution Approach 2:
The orifice plate is a simple, inexpensive component with a straightforward geometry that can be easily manufactured and installed. Rather than implementing a complex active control system, the patent uses this passive, low-cost component to achieve frequency modification and reduce modal coupling.
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 reduces the amplitude and frequency of combustion dynamics, minimizing the likelihood of unwanted vibratory responses in downstream components by varying combustion dynamics across combustors, thereby mitigating potential vibrational stress and performance degradation.
Implementation Method 1
a second orifice plate disposed in a second fuel path upstream of the second fuel injector, wherein the second orifice plate is configured to help reduce modal coupling between the first combustor and the second combustor
Data Source
AI summary
A system includes a gas turbine engine that includes a first combustor and a second combustor. The first combustor includes a first fuel nozzle disposed in a first head end chamber of the first combustor and a first fuel injector. The first fuel nozzle is configured to inject a first fuel and an oxidant into a first combustion chamber of the first combustor. The second combustor includes a second fuel nozzle disposed in a second head end chamber of the second combustor, a second fuel injector, and a second orifice plate disposed in a second fuel path upstream of the second fuel injector. The second fuel nozzle is configured to inject the first fuel and the oxidant into a second combustion chamber of the second combustor and the second orifice plate is configured to help reduce modal coupling between the first combustor and the second combustor.