Gas Turbine Injector Passages for Coking-Resistant Cooling
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Solution Overview
Problem
Conventional fuel injectors for gas turbine engines face challenges with coking, which leads to solid deposits and restricted fuel flow due to inadequate thermal management, potentially causing hardware distress and failure.
Innovation Solution
The design incorporates additively manufactured primary and secondary fluid passages with nonlinear sections, where the secondary passage circles around the primary in a helical shape, providing extended residence time for cooling fluid and a monolithic heat shield, enhancing thermal management and cooling capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional linear fuel passages are used, then the injector structure is simple, but the cooling fluid residence time is insufficient leading to coking and restricted fuel flow
Solution Approach 1:
The patent applies curvature by transforming the conventional linear fuel passage into a nonlinear serpentine configuration. The cooling fluid passage winds through the feed arm in a curved path rather than a straight line, increasing the residence time of cooling fluid in contact with the passage walls. This curved geometry enhances heat extraction from the fuel passages, preventing coking and maintaining reliable fuel flow without requiring additional cooling components.
2Temperature
If the cooling fluid passage is made linear, then the passage length is short, but the cooling capacity is insufficient to prevent metal temperatures from exceeding maximum values
Solution Approach 1:
The patent utilizes three-dimensional spatial arrangement by routing the cooling fluid passage through the interior volume of the feed arm in a serpentine pattern. Instead of extending the passage linearly in one direction, the cooling fluid travels through multiple dimensions within the feed arm's cross-section, creating a compact yet extended cooling path. This dimensional approach increases the effective cooling surface area and residence time while maintaining a compact overall injector structure.
3Reliability
If separate cooling passages are added for each fuel passage, then the cooling coverage is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent combines multiple cooling functions into a single integrated serpentine cooling passage that serves the entire feed arm structure. Rather than providing separate cooling passages for each fuel passage, the unified nonlinear cooling path winds through the feed arm and provides cooling coverage for all fuel passages along its route. This merging approach maintains comprehensive cooling coverage while significantly simplifying manufacturing, as the entire cooling system can be formed in a single piece using additive manufacturing techniques.
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 configuration significantly reduces metal temperatures within the fuel passages, preventing coking and maintaining fuel flow efficiency, resulting in a more reliable and durable fuel injector.
Implementation Method 1
the nonlinear section of the secondary fluid passage provides extended residence time for cooling fluid in the first and second fluid passages
Implementation Method 2
the nonlinear section of the secondary fluid passage circles around a linear section of the primary fluid passage in a helical shape
Data Source
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AI summary
An injector (100) for a gas turbine engine includes a feed arm (102) including a primary and a secondary fluid passage (110, 112). An inlet assembly (104) is fixed at an upstream end of the feed arm (102) having at least one inlet (107, 108) in fluid communication with the primary and the secondary fluid passages (110, 112). A tip assembly (106) is fixed at a downstream end of the feed arm (104) having a fluid outlet (114) in communication with the primary and secondary fluid passages (110, 112) for issuing a spray of fluid. The primary and secondary fluid passages (110, 112) are monolithically formed within the feed arm (102). At least one of the primary and secondary fluid passages (110, 112) includes a nonlinear section configured to provide increased residence time for cooling fluid in the first and second fluid passages (110, 112).