Monolithic Fuel Injector Nozzle for Additive Manufacturing
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Solution Overview
Problem
Conventional fuel injectors for gas turbine engines face challenges in creating nozzle assemblies with easy-to-make fluid passages that are resistant to dynamic and static loads, corrosive environments, and high temperatures, while also requiring improved reliability, weight efficiency, and durability.
Innovation Solution
A fuel injector with a monolithic nozzle body featuring a fuel circuit that includes a main passage and a branch passage, where the branch passage diverges and rejoins the main passage to create an effective metering flow area smaller than the outlet orifice, allowing for additive manufacturing techniques that tolerate surface roughness and complex geometries, and incorporating a prefilmer for air blasting to atomize fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional casting and machining processes are used to manufacture fuel injector nozzle bodies, then manufacturing precision and surface finish can be achieved, but the ability to create complex internal geometries and integrate components is limited
Solution Approach 1:
The patent combines multiple previously separate components (nozzle body, internal passages, mounting features) into a single monolithic structure manufactured by additive manufacturing. This integration eliminates the need for separate machining operations and assembly steps, directly resolving the contradiction between geometric complexity and manufacturing ease.
Solution Approach 2:
Additive manufacturing enables the creation of three-dimensionally complex internal geometries that cannot be achieved through conventional machining from bar stock. The layer-by-layer construction approach allows fluid passages and structural features to be formed in all three dimensions simultaneously, transforming the manufacturing paradigm from subtractive to additive.
2Shape
If additive manufacturing is used to create nozzle bodies, then complex structures and integrated components can be formed, but surface roughness increases compared to casting and machining
Solution Approach 1:
The patent applies different surface quality requirements to different regions of the nozzle body. Critical flow passages and outlet surfaces maintain smooth finishes through controlled additive manufacturing parameters, while non-critical external surfaces can tolerate greater roughness. This localized approach to surface quality resolves the contradiction between geometric complexity and overall surface precision.
3Manufacturing precision
If traditional metering orifices are used in fuel circuits, then flow control is achieved through precise orifice geometry, but performance is highly sensitive to surface roughness and manufacturing tolerances
Solution Approach 1:
The patent changes the fundamental parameter used for flow control from relying on small orifice dimensions (highly sensitive to roughness) to using larger flow areas with controlled pressure gradients. The additive manufacturing process enables precise control of passage geometry and surface texture, allowing flow parameters to be optimized independently of surface roughness effects.
4Weight of moving object
If conventional nozzle designs are used, then manufacturing processes are well-established, but the ability to optimize for weight and performance is limited
Solution Approach 1:
The additive manufacturing process allows the nozzle body to be designed as an optimized monolithic structure rather than assembling multiple machined components. This segmentation at the design level (creating an integrated structure) enables weight reduction through elimination of material and joints, while the manufacturing process matures through standardized additive production methods.
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 enables the construction of fuel injectors with superior flow rates and pressure drop characteristics, decoupling performance from flow area geometry and reducing sensitivity to surface roughness, enabling the use of additive manufacturing processes that would otherwise be unsuitable for conventional nozzles.
Implementation Method 1
The outlet orifice of the fuel circuit is disposed adjacent to the prefilmer such that fuel issuing from the outlet orifice flows across a surface of the prefilmer and atomized by air traversing the prefilmer
Data Source
AI summary
A fuel injector 100 for a gas turbine engine includes a monolithic nozzle body 102 that defines within its interior one or more fuel circuits 110. Each fuel circuit includes an inlet 112, an outlet orifice 114, a main passage 118 fluidly coupling the inlet with the outlet orifice, and a branch passage 120 connected to the main passage. The branch passage 120 connects to the main passage downstream of the inlet and upstream of the outlet orifice to form an effective metering flow area that is smaller than the flow area of the outlet orifice.