Fuel Nozzle Turning Guide for Uniform Air Distribution
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Solution Overview
Problem
In gas turbines, uneven air flow due to air pockets can lead to unstable combustion, increased NOx production, and potential damage to fuel nozzle components, as the flow rate of air is not consistently maintained, causing local changes in the air-fuel mixture and temperature.
Innovation Solution
A fuel nozzle assembly with a turning guide and rim configuration that includes a turning separator and inner separators to distribute air uniformly, controlling the circumferential distance between the turning separator and the rim to prevent air pocket formation and ensure consistent air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If compressed air is changed in direction when introduced into a fuel nozzle assembly, then air can be directed into the combustion chamber, but an air pocket is generated causing uneven air flow
Solution Approach 1:
The fuel nozzle assembly is divided into multiple independent nozzles arranged in an array, with each nozzle having its own flow path and air supply channel. This segmentation allows each nozzle to maintain uniform air flow independently, preventing the formation of air pockets that would occur in a single-direction air supply system.
Solution Approach 2:
The air supply system transitions from a single-direction linear flow to a multi-dimensional radial flow pattern by introducing air from multiple directions through the array of nozzles. This dimensional change in air flow distribution eliminates stagnant regions and ensures uniform air supply throughout the combustion chamber.
2Stability of the object's composition
If air flow rate is reduced to match fuel injection, then fuel can be properly mixed with air, but air pockets form causing unstable combustion
Solution Approach 1:
Each nozzle in the array is designed with specific local characteristics, including individually adjustable flow rates and optimized air-fuel mixing ratios. This allows each local region to achieve optimal mixing conditions while maintaining overall combustion stability, preventing both air pockets and fuel-rich zones.
Solution Approach 2:
The system dynamically adjusts operational parameters such as air flow rate, fuel injection rate, and nozzle geometry to maintain optimal air-fuel ratios throughout the combustion chamber. This parameter optimization ensures complete fuel combustion while preventing air pocket formation and maintaining combustion stability.
3Power
If low-rate air flow is allowed, then fuel can be injected at higher rates, but flames generate inside the fuel nozzle causing damage
Solution Approach 1:
Air is supplied to each nozzle before fuel injection begins, pre-establishing a protective air barrier and optimal mixing conditions. This preliminary air supply prevents flame propagation into the fuel nozzle structure during subsequent high-rate fuel injection, eliminating the harmful effect of flame damage while maintaining high power output.
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 solution effectively prevents air pocket generation, ensures uniform air supply, stabilizes combustion, reduces NOx production, and prevents damage to fuel nozzle components by maintaining consistent air flow and mixing.
Implementation Method 1
a turning guide spaced apart from the rim and configured to distribute a flow of the air to be introduced into the flow path
Implementation Method 2
a rim formed along an outer circumference of an inlet of the shroud to guide air to the flow path
Implementation Method 3
a fuel nozzle configured to supply a fuel to a combustion chamber
Implementation Method 4
a shroud spaced apart from the fuel nozzle to surround the fuel nozzle and define a flow path between an inner wall thereof and the fuel nozzle
Data Source
AI summary
Disclosed are a fuel nozzle assembly, and a fuel nozzle module and gas turbine having the same. The fuel nozzle assembly includes a fuel nozzle, a shroud spaced apart from the fuel nozzle and defining a flow path between an inner wall and the fuel nozzle, a rim formed around the shroud to guide air, and a turning guide spaced apart from the rim to distribute the air. The turning guide includes a turning separator spaced apart from the rim to extend in a circumferential direction of the rim, and inner separators extending in a radial direction of the rim to interconnect opposite circumferential ends of the turning separator and an outer surface of the fuel nozzle. The fuel nozzle assembly prevents air pockets, and ensures uniform supply of air, thereby preventing a local increase in combustion temperature inside the fuel nozzle and reducing generation of NOx.