Spiral Fuel Nozzle Burner for NOx and Reverse Fire Suppression
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Solution Overview
Problem
Existing combustors face issues with high fuel-air ratio regions leading to increased NOx generation and reverse fires due to swirling flow dynamics.
Innovation Solution
A burner design with a mixing pipe and fuel nozzle featuring a spiral-shaped protrusion portion that separates from the inner peripheral surface, promoting swirling flow and small turbulence to enhance fuel-air mixing while suppressing high fuel-air ratios and reverse fires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a swirling flow is generated in the air hole to separate fuel and air, then reverse fire is suppressed, but a high fuel-air ratio region is generated near the central axis leading to increased NOx generation
Solution Approach 1:
The invention applies local quality by creating different flow characteristics in different regions: a swirling flow is generated in the inner peripheral region to prevent reverse fire, while a diffuser structure is provided in the central region to reduce flow speed and promote mixing, thereby preventing high fuel-air ratio concentration and NOx generation.
Solution Approach 2:
The air hole is segmented into functionally distinct regions: an inner peripheral portion that generates swirling flow for reverse fire suppression, and a central portion with a diffuser structure for controlled mixing and NOx prevention. This segmentation allows each region to perform its specific function optimally.
2Stability of the object's composition
If compressed air flows through the air hole with swirling groove, then fuel-air separation is achieved, but the gas flow rate becomes uneven creating high fuel-air ratio regions
Solution Approach 1:
The invention applies local quality by creating different flow characteristics in different regions: a swirling flow is generated in the inner peripheral region to prevent reverse fire, while a diffuser structure is provided in the central region to reduce flow speed and promote mixing, thereby preventing high fuel-air ratio concentration and NOx generation.
Solution Approach 2:
The diffuser structure changes the flow parameters by reducing the gas flow rate in the central region through gradual expansion, which promotes better mixing between fuel and air and prevents the formation of high fuel-air ratio regions that would lead to NOx generation.
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 effectively suppresses NOx generation and reverse fires by optimizing fuel-air mixing and flow dynamics, ensuring efficient combustion.
Implementation Method 1
the compressed air becomes a swirling flow due to the swirling groove formed on the inner peripheral surface of the air hole
Implementation Method 2
the compressed air is pressed against the inner peripheral surface side of the air hole due to a centrifugal force
Implementation Method 3
a small turbulence of the air is generated on the downstream side in an air crossing direction on the outer peripheral surface
Implementation Method 4
a mixing space for mixing air and fuel is formed in the mixing pipe
Implementation Method 5
a combustor that combusts fuel with the air compressed by the compressor to generate combustion gas
Data Source
AI summary
This burner comprises a mixing pipe in which a mixing space is formed, and a fuel nozzle disposed in the mixing space. The fuel nozzle comprises a nozzle main body extending in an extension direction of the mixing space, and a projecting portion which projects out from an outer circumferential surface of the nozzle main body and which is spaced apart from an inner circumferential surface of the mixing pipe. The nozzle main body has a fuel ejection port capable of ejecting fuel into the mixing space. The projecting portion gradually extends to a downstream side in the extension direction as it extends in a circumferential direction relative to the nozzle main body, and the entire projecting portion is formed in a spiral shape around the nozzle main body.