Fuel Injector With a Tapered Gallery for Low-Pressure Flow
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Solution Overview
Problem
Existing fuel injectors for turbine engines suffer from issues such as increased likelihood of coking due to fuel stagnation and high pressure requirements, especially with decreasing fuel flow velocities and pressures, which affect efficiency and performance.
Innovation Solution
A fuel injector design featuring a tapered fuel gallery with varying cross-sectional area and geometry to maintain uniform fuel velocity and reduce pressure drop, incorporating multiple feed and exit passages to optimize fuel distribution and minimize coking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional annular fuel gallery is used to distribute fuel to multiple exit passages, then the fuel distribution structure is simple, but fuel stagnation occurs leading to increased coking likelihood
Solution Approach 1:
The fuel gallery cross-sectional area is varied locally along its length, being larger at the inlet end and smaller at the outlet end. This local variation in geometry creates different flow conditions at different locations, maintaining higher fuel velocities throughout the gallery and preventing stagnation that leads to coking.
Solution Approach 2:
The cross-sectional area parameter of the fuel gallery is changed progressively along its length rather than remaining constant. This parameter change optimizes fuel flow velocity distribution, ensuring adequate flow rates to all exit passages while preventing fuel stagnation and reducing coking risk.
2Speed
If high fuel pressure is used to maintain flow velocity, then fuel delivery is reliable, but pressure requirements increase the system complexity
Solution Approach 1:
The fuel gallery cross-sectional area is progressively reduced from inlet to outlet, which maintains higher fuel velocities throughout the gallery without requiring proportionally higher inlet pressures. This geometric parameter change optimizes the pressure-velocity relationship.
Solution Approach 2:
The tapered geometry of the fuel gallery creates a gradual transition in flow area, which smooths pressure drops and reduces the overall pressure requirement compared to abrupt changes or constant area configurations.
3Stress or pressure
If the fuel gallery cross-sectional area is reduced to lower pressure requirements, then pressure drop decreases, but fuel velocity uniformity across exit passages deteriorates
Solution Approach 1:
The fuel gallery employs locally varied cross-sectional areas that are specifically optimized at different positions. The larger area at the inlet accommodates higher flow rates, while the progressively smaller areas toward the outlet maintain appropriate velocities for each local section, ensuring uniform fuel delivery to all exit passages.
Solution Approach 2:
The cross-sectional area parameter is changed progressively along the gallery length to balance pressure drop reduction with velocity uniformity maintenance. This controlled parameter change ensures that fuel velocity remains sufficiently high at all exit passages while keeping overall pressure requirements manageable.
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 reduces the likelihood of fuel coking and lowers pressure requirements, enhancing efficiency and performance by maintaining uniform fuel velocity and reducing fuel flow time in the nozzle, suitable for low-pressure fuel systems and smaller fuel flows.
Implementation Method 1
maintain uniform fuel velocity and reduce pressure drop
Implementation Method 2
fuel flow time in the nozzle
Data Source
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AI summary
A fuel injector (64) is provided for a turbine engine (20). This fuel injector (64) includes a fuel nozzle (80), and the fuel nozzle (80) includes a gallery (98), one or more feed passages (100) and a plurality of exit passages (102). The gallery (98) extends within the fuel nozzle (80) circumferentially around an axis (106) between a first end (116) of the gallery (98) and a second end (118) of the gallery (98). A size of the gallery (98) changes as the gallery (98) extends circumferentially around the axis (106) between the first end (116) of the gallery (98) and the second end (118) of the gallery (98). The one or more feed passages (100) extend within the fuel nozzle (80) to the gallery (98). The one or more feed passages (100) are configured to supply fuel to the gallery (98). The exit passages (102) extend within the fuel nozzle (80) from the gallery (98). The exit passages (102) are configured to receive the fuel from the gallery (98).