Fuel Nozzle Flexible Support Structures for Thermal Stress Isolation
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Solution Overview
Problem
Gas turbine engine fuel nozzles face challenges in mechanically and thermally isolating internal structures to prevent thermal stresses and carbon deposits, while also requiring sufficient stiffness to withstand vibrations and maintain fuel flow efficiency.
Innovation Solution
A staged fuel nozzle design incorporating flexible support structures, such as cantilevered support arms, that connect static and fuel discharge elements, providing structural support while maintaining flexibility to absorb thermal and mechanical stresses, and manufactured using additive manufacturing processes for enhanced integration and reduced stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid internal support structures are used, then structural stiffness is improved to withstand vibrations, but thermal isolation is worsened leading to thermal stresses and heat-induced carbon deposits
Solution Approach 1:
The patent employs flexible support structures with L-shaped configurations that act as thermal barriers while providing mechanical support. These thin-walled flexible structures isolate hot and cold portions of the fuel nozzle, preventing thermal stress and heat-induced carbon deposits while maintaining structural integrity under vibration.
2Object-affected harmful factors
If flexible support structures are used, then thermal isolation is improved to prevent thermal stresses, but structural stiffness is worsened leading to potential fatigue failure and undesired harmonic behavior
Solution Approach 1:
The flexible support structures are designed with L-shaped configurations that provide dynamic compliance to accommodate thermal expansion and vibration while maintaining sufficient stiffness to prevent fatigue failure. The structures adapt their rigidity based on operational conditions, balancing thermal isolation with mechanical strength.
3Object-affected harmful factors
If complex internal support structures are used, then mechanical and thermal isolation is improved, but device complexity increases making manufacturing and assembly more difficult
Solution Approach 1:
The fuel nozzle is divided into distinct functional segments: a stationary portion, a flexible support structure, and a fuel discharge element. This segmentation allows each component to be optimized independently for its specific function while simplifying manufacturing and assembly processes through modular construction.
Solution Approach 2:
The flexible support structure is nested within the fuel nozzle assembly, with the fuel discharge element positioned within the stationary portion. This nested configuration reduces overall complexity by integrating multiple functions into a compact, hierarchical structure that is easier to manufacture and assemble.
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 effectively isolates hot and cold portions of the nozzle, reducing thermal and mechanical stresses, preventing coking, and maintaining fuel flow efficiency by distributing mechanical and thermal loads evenly, thus enhancing the durability and performance of the fuel nozzle.
Implementation Method 1
The flexible support structure is configured to perform as a spring element
Data Source
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AI summary
A fuel nozzle apparatus (10) for a gas turbine engine includes: a fuel discharge element (24) having a discharge orifice (50) communicating with a fuel supply connection (104); a static supporting structure (36); and a cantilevered flexible support structure (110) interconnecting the supporting structure (36) and the fuel discharge element (24), the flexible support structure (110) having a first end connected to the static supporting structure (36), and a second end connected to the fuel discharge element (24).