Combustor Nozzle Cooling Layout for Hydrogen Flashback Prevention
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Solution Overview
Problem
Existing gas turbines using hydrogen fuel face issues with flame flashback due to temperature rise at the nozzle outlet, which is sensitive to fuel/air mixture supply speed and wall surface temperature.
Innovation Solution
A nozzle assembly with injection nozzles that incorporates a cooling air inlet and outlet system to supply compressed air for cooling, preventing thermal damage and flame flashback by maintaining nozzle tip temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If hydrogen fuel is combusted to reduce carbon emissions, then environmental performance is improved, but flame flashback risk increases due to temperature rise at the nozzle outlet
Solution Approach 1:
Cooling air is introduced as an intermediary substance between the fuel/air mixture and the nozzle outlet wall. This cooling air flows through cooling passages in the nozzle body and exits at the nozzle outlet, forming a protective layer that prevents the hot combustion mixture from directly contacting the nozzle wall, thereby preventing flame flashback while maintaining hydrogen combustion benefits
Solution Approach 2:
Cooling air is supplied to the nozzle outlet region before the fuel/air mixture exits and before combustion occurs. By pre-cooling the nozzle outlet surface and introducing cool air into the mixture, the system prepares a protective environment that prevents flame flashback before it can occur
2Productivity
If the fuel/air mixture supply speed is increased to improve combustion efficiency, then productivity is improved, but flame flashback sensitivity increases
Solution Approach 1:
Cooling air acts as a mediator that decouples the relationship between high supply speed and flame flashback risk. By introducing this intermediate cooling flow, the system can maintain high fuel/air mixture supply speeds for improved combustion efficiency while the cooling air prevents direct flame contact with the nozzle, reducing flashback sensitivity
3Reliability
If the nozzle outlet temperature is reduced to prevent flame flashback, then reliability is improved, but combustion efficiency may deteriorate
Solution Approach 1:
Cooling air is applied locally at the nozzle outlet region rather than throughout the entire combustion system. This localized cooling maintains low temperatures at the critical nozzle outlet surface to prevent flame flashback while allowing the bulk combustion process to proceed at high temperatures for maintained efficiency
Solution Approach 2:
Cooling air serves as a local intermediary that creates a temperature gradient at the nozzle outlet. The cool air layer protects the nozzle surface and immediate outlet region, while the hot combustion gases maintain high temperatures in the combustion chamber for efficient combustion
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 cooling system effectively protects the injection nozzles from thermal stress and prevents flame flashback, enhancing the safety and efficiency of the gas turbine operation.
Implementation Method 1
a cooling air inlet hole configured to receive a second portion of the compressed air into the accommodation space of the nozzle body for cooling the plurality of injection nozzles
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Nozzle assembly (1000), combustor(100) and gas turbine (10). Fuel and compressed air are discharged to a combustion chamber (120a) of the combustor of the gas turbine. The nozzle assembly includes a nozzle body, (1100), a plurality of injection nozzles (1200) provided inside the nozzle body and disposed to be spaced apart from each other, the injection nozzles having inner portions through which the compressed air and the fuel are mixed and moved, and a side wall (1300) which is connected to a first side of the nozzle body and through which the injection nozzles passes. A cooling air inlet hole (1110) into which cooling air is introduced into a space where the injection nozzles are disposed is formed in the nozzle body, and a cooling air outlet hole (1310) through which the cooling air introduced from the cooling air inlet hole is discharged is formed in one region of the side wall.