Hemispherical Dome Fuel Nozzle for Gas Turbine Emissions
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Solution Overview
Problem
Current fuel nozzle designs in gas turbine engines, particularly diffusion type nozzles, result in high emissions of NOx and CO due to inefficient fuel and air mixing, which can be improved by premixing fuel and air before combustion, but the effectiveness of this mixing depends on the air supply and mixing quality.
Innovation Solution
A fuel nozzle assembly with a hemispherically-shaped dome and swirler vanes is used to direct and condition the compressed air, creating a swirl and ensuring thorough mixing by orienting openings in both axial and radial components to enhance air-fuel interaction, eliminating the need for turning vanes and improving mixing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If diffusion type nozzles are used for fuel injection, then combustor stability is maintained at high temperature, but emissions of NOx and CO increase due to inefficient mixing
Solution Approach 1:
The patent applies preliminary action by introducing air conditioning screens and swirler vanes upstream of the combustion zone to pre-condition and swirl the air flow before fuel injection. This preliminary conditioning enhances the mixing effectiveness between fuel and air, allowing for more complete combustion and reduced emissions of NOx and CO while maintaining combustor stability.
Solution Approach 2:
The patent employs curved and swirler vanes that create a swirling motion in the air flow. This curvature and swirl pattern enhances the mixing between fuel and air by creating a more uniform distribution and increasing the contact time between the two substances, thereby improving combustion efficiency and reducing harmful emissions.
2Object-generated harmful factors
If premixing of fuel and air is implemented, then combustion temperature decreases and NOx emissions reduce, but mixing completeness depends on air supply effectiveness
Solution Approach 1:
The patent segments the air supply system into multiple zones using air conditioning screens with different opening patterns and orientations. This segmentation allows different portions of the air flow to be conditioned differently, optimizing the mixing process at various stages and ensuring complete premixing without requiring overly complex single-stage conditioning systems.
Solution Approach 2:
The patent introduces air conditioning screens and swirler vanes as intermediary components between the air supply and the combustion zone. These intermediaries condition the air flow by creating swirl patterns and uniform distributions, facilitating effective premixing of fuel and air while keeping the overall system design manageable and not excessively complex.
3Quantity of substance
If air conditioning screens with multiple openings are added, then mixing effectiveness improves, but device complexity increases
Solution Approach 1:
The air conditioning screens in the patent serve multiple functions simultaneously: they condition the air flow, create swirl patterns, distribute fuel and air uniformly, and stabilize the combustion process. By making these components multi-functional, the patent achieves thorough mixing without adding excessive numbers of separate components, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent combines multiple functions into integrated components. The air conditioning screens are merged with swirler vanes and positioning structures, creating unified elements that perform flow conditioning, mixing, and structural support functions simultaneously. This merging reduces the total number of discrete components while maintaining mixing effectiveness.
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 design enhances the mixing of fuel and air, leading to reduced emissions by ensuring a more homogeneous mixture burns completely, aligning with the goal of lowering NOx and CO emissions in gas turbine engines.
Implementation Method 1
a plurality of swirler vanes contained therein for inducing a swirl into a passing flow of air and fuel
Implementation Method 2
a hemispherically-shaped dome extending around an inlet end of the premix tube positioned towards a base of the fuel nozzle assembly, and having a plurality of openings oriented in both an axial and radial component
Implementation Method 3
An enhancement in combustion technology is the concept of premixing fuel and air prior to combustion to form a homogeneous mixture that burns at a lower temperature than a diffusion type flame and thereby produces lower NOx emissions
Implementation Method 4
when ignited will burn more completely, resulting in lower emissions
Data Source
AI summary
The present invention discloses a novel apparatus and way for directing a supply of compressed air into a fuel nozzle assembly for mixing with a fuel source. The apparatus comprises a fuel nozzle assembly having a plurality of coaxial tubes and radially-extending swirler vanes for directing a supply of fuel to a mixing tube. Compressed air is directed to flow in a primarily axial direction by passing through a hemispherically-shaped dome portion at an air inlet region of the fuel nozzle assembly. The hemispherically-shaped dome includes a plurality of openings for directing air into the fuel nozzle assembly in a direction having a radial and axial component.