Dual Fuel Nozzle with Liquid Filming Atomization
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Solution Overview
Problem
Gas turbine engines face challenges in achieving uniform fuel distribution and swirl patterns due to high water-to-fuel ratios in dual fuel nozzles, leading to increased NOx emissions and decreased circumferential uniformity.
Innovation Solution
The design incorporates an outer air swirler and an inner air swirler with annular passages for fuel gas and liquid, featuring convergent-divergent nozzles and helical inflow tubes to optimize airflow and liquid injection, reducing the water-to-fuel ratio and enhancing swirl momentum and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water is injected through the nozzle to reduce NOx emissions, then NOx emissions are reduced, but the water-to-fuel ratio becomes undesirably high and circumferential uniformity decreases
Solution Approach 1:
The nozzle is divided into multiple independent liquid injection passages (first, second, third liquid passages) that inject water at different locations and angles. This segmentation allows each passage to contribute to different regions of the combustion chamber, achieving more uniform water distribution and preventing excessive water-to-fuel ratio in any single region, thereby maintaining circumferential uniformity while still reducing NOx emissions
Solution Approach 2:
Different liquid passages are designed with different injection characteristics (different angles, different locations, different passage geometries) to optimize water injection in specific local regions. For example, the first liquid passage injects at a first angle while the second liquid passage injects at a second angle, creating locally optimized injection patterns that collectively achieve uniform overall distribution while reducing NOx
2Object-affected harmful factors
If water is injected through the nozzle to reduce NOx emissions, then NOx emissions are reduced, but the water-to-fuel ratio becomes undesirably high
Solution Approach 1:
The liquid injection system is segmented into multiple passages that distribute water more efficiently across the fuel stream. This allows for effective NOx reduction with a lower overall water-to-fuel ratio, as the segmented injection ensures better water-fuel mixing and utilization, preventing waste of water and achieving emission reduction at lower injection rates
Solution Approach 2:
The nozzle utilizes hydraulic principles in the design of liquid passages with specific geometries (convergent-divergent shapes, inclined sections) that optimize liquid flow and atomization. This efficient hydraulic design ensures that water is injected and mixed with fuel in a manner that maximizes NOx reduction effectiveness per unit of water injected, thereby reducing the required water-to-fuel ratio
3Stability of the object's composition
If multiple liquid passages are used to improve uniformity, then circumferential uniformity improves, but device complexity increases
Solution Approach 1:
The multiple liquid passages are nested within a single nozzle body structure, with each passage integrated into the overall nozzle geometry. The passages are arranged concentrically or in a nested configuration that allows them to function independently while maintaining a compact, unified nozzle structure, thereby achieving improved uniformity without proportionally increasing overall device complexity
Solution Approach 2:
The nozzle structure is designed as a multi-functional component that simultaneously handles multiple liquid fuel streams through different passages. The single nozzle body serves multiple functions: it contains all liquid passages, provides structural support, enables atomization, and controls flow distribution. This universal design achieves improved uniformity through multiple passages while avoiding the complexity of separate injection devices
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 improves fuel-air mixing, reduces NOx emissions, and achieves better circumferential uniformity by optimizing the swirl pattern and water vaporization, allowing for lower water injection rates.
Implementation Method 1
the liquid at least partially impacting upon a filming region of a convergent divergent nozzle
Implementation Method 2
An air inflow tube with a helical inflow vane along the axis within the inner air swirler
Implementation Method 3
the outer wall defines a convergent-divergent nozzle
Implementation Method 4
achieves better circumferential uniformity by optimizing the swirl pattern and water vaporization
Data Source
AI summary
A fuel nozzle for a combustor of a gas turbine engine includes an outer air swirler along an axis, said outer air swirler defines an outer annular air passage between an outer wall and an inner wall, the outer wall defines a convergent-divergent nozzle. An inner air swirler along the axis to define an annular liquid passage therebetween, the annular liquid passage terminates upstream of the convergent-divergent nozzle and an annular fuel gas passage around the axis between the outer air swirler and the inner air swirler.