Additively Manufactured Fuel Injector with Thermal Compliance
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Solution Overview
Problem
Conventional fuel injector designs for gas turbine engines face challenges due to differential thermal expansion, leading to stresses, leaks, coking contamination, and fluid dynamic concerns, which are difficult to address with complex assemblies and costly manufacturing processes.
Innovation Solution
A fuel injector is additively manufactured as a single unitary piece with thermally compliant features, allowing for differential thermal expansion without imparting stresses on internal components, using techniques like Selective Laser Sintering or Electron Beam Melting, and incorporating geometries that provide displacement capacity, such as gaps or elastic portions, to accommodate temperature gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional assembly methods with multiple parts and braze joints are used to accommodate thermal expansion, then thermal compliance is achieved, but manufacturing complexity, weight, and cost increase
Solution Approach 1:
The patent merges multiple separate components (fuel circuit, support structure, sealing elements, and thermal expansion compensation features) into a single monolithic structure fabricated via additive manufacturing. This integration eliminates the need for complex assemblies of over thirty individual parts and braze joints, while maintaining thermal compliance through built-in compliant features designed at the digital model level.
Solution Approach 2:
The invention changes the manufacturing method from conventional subtractive or assembly-based processes to additive manufacturing, enabling the creation of complex internal geometries and thermally compliant features that are impossible or prohibitively expensive to achieve with traditional methods. This parameter change in fabrication technology resolves the contradiction between thermal compliance and manufacturing complexity.
2Reliability
If conventional assembly methods with multiple parts are used, then thermal expansion accommodation is possible, but manufacturing time and cost increase
Solution Approach 1:
The thermally compliant features are designed and embedded in the digital 3D model before manufacturing. The additive manufacturing process then directly fabricates these complex geometries in a single operation, eliminating the need for subsequent assembly operations, braze joining, and sealing installation that would otherwise be required to achieve thermal expansion accommodation.
Solution Approach 2:
By combining all functional elements into a single monolithic component, the invention eliminates multiple manufacturing steps including separate fabrication of individual parts, braze joining operations, and assembly operations. This single-step additive manufacturing process dramatically improves manufacturing efficiency while maintaining thermal expansion accommodation capabilities.
3Strength
If conventional assembly with braze joints is used, then structural integrity is achieved, but weight and manufacturing complexity increase
Solution Approach 1:
The patent eliminates the need for braze joints by merging all components into a single monolithic structure. This removal of intermediate joining elements reduces the overall weight of the fuel injector while maintaining structural integrity through the continuous material structure provided by additive manufacturing, which can optimize material distribution to maintain or improve strength-to-weight ratio.
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 approach reduces manufacturing complexity, weight, and cost while preventing leaks and contamination by allowing the fuel injector to adjust to thermal gradients, enhancing reliability and lifespan.
Implementation Method 1
Differences in temperature between exterior fuel injector features and interior fuel injector features can exceed several hundreds of degrees (Fahrenheit). This results in differential thermal expansion or displacement of the exterior features relative to the interior features.
Implementation Method 2
an additive manufacturing process such as selective laser sintering
Implementation Method 3
an additive manufacturing process such as selective laser sintering or electron beam melting
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
One embodiment includes a fuel injector. The fuel injector assembly comprises a conduit for conveying fuel from a fuel inlet to a nozzle. The conduit is located in a support, with the conduit, the nozzle, and the support being a single unitary piece. A thermally compliant feature is located at the nozzle which allows the fuel injector to adjust for differential thermal expansion.