Gas Turbine Secondary Nozzle Fuel Flexibility
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Solution Overview
Problem
Conventional secondary nozzles in gas turbine systems are complex, limit the use of high reactivity fuels due to flame-holding risks, and are prone to permanent damage during combustion operations.
Innovation Solution
A simplified secondary nozzle design featuring a center body, burner tube, and outer peripheral wall with integrated pilot and transfer passages, including swirl vanes for fuel-air mixing and air cooling, which allows for efficient fuel distribution and cooling to prevent damage from flame-holding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate passages are provided for pilot fuel, transfer fuel, and air in the secondary nozzle, then the nozzle can perform multiple functions (supplying fuel for fully premixed mode, supplying fuel and air for pilot flame, providing transfer fuel), but the nozzle assembly becomes complex
Solution Approach 1:
The patent combines multiple functions into a single integrated secondary nozzle structure. The center body contains both the pilot fuel passage and transfer fuel passage, while the burner tube provides the fuel-air mixing passage. This merging of functions into a unified structure eliminates the need for separate nozzle assemblies for pilot fuel, transfer fuel, and air supply, thereby reducing overall nozzle assembly complexity while maintaining multi-functionality.
Solution Approach 2:
The secondary nozzle is designed as a universal component that performs multiple functions: it supplies fuel for fully premixed mode operation, provides fuel and air for pilot flame support, and delivers transfer fuel during mode transitions. The center body with its integrated passages and the burner tube work together as a single multi-functional unit, allowing one nozzle assembly to replace what would traditionally require multiple separate components.
2Adaptability or versatility
If high reactivity fuels are used in the pilot, then fuel flexibility is improved, but the risk of flame-holding increases which can cause permanent damage to the nozzle
Solution Approach 1:
The burner tube acts as an intermediary component between the pilot fuel passage and the combustion zone. It provides a controlled fuel-air mixing passage that regulates the interaction between high reactivity pilot fuel and air, preventing direct flame-holding against the nozzle walls. This intermediary structure allows high reactivity fuels to be used while protecting the nozzle from damage by controlling where and how combustion occurs.
Solution Approach 2:
The patent extracts the flame-holding function from the nozzle body itself and relocates it to the burner tube outlet where a fuel-air mixture is formed. By separating the fuel delivery function (center body passages) from the combustion function (burner tube mixing zone), the design allows high reactivity fuels to be delivered safely while preventing flame attachment to sensitive nozzle surfaces that would cause damage.
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 design enhances fuel flexibility, enables the use of high reactivity fuels, and protects the nozzle from damage during prolonged flame exposure, reducing NOx emissions and extending the combustor's fuel flexibility envelope.
Implementation Method 1
swirl vanes for fuel-air mixing
Implementation Method 2
air cooling
Data Source
AI summary
A nozzle for a combustor is disclosed. The nozzle includes a center body, a burner tube provided around the center body and defining a fuel-air mixing passage therebetween, and an outer peripheral wall provided around the burner tube and defining an air flow passage therebetween. The nozzle further includes a nozzle tip connected to the center body. The nozzle tip includes a pilot fuel passage configured to deliver a flow of pilot fuel to a combustion zone, and a plurality of transfer passages. The plurality of transfer passages are configured to deliver a flow of air for combustion with the flow of pilot fuel in the combustion zone and further configured to deliver a flow of transfer fuel to the combustion zone.