Fuel Injector Shroud Interior Ribs for NOx Reduction
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Solution Overview
Problem
Gas turbine engines face challenges in reducing NOx emissions and managing temperature characteristics, particularly in RQL combustors, where fuel injector shrouds are susceptible to high temperatures and thermal stresses, affecting durability and airflow conditioning.
Innovation Solution
A fuel injector assembly with a swirler device and interior ribs in the fuel injector shroud that directs air flow to mix with fuel, enhancing mixing and reducing NOx emissions, while also improving durability and airflow conditioning through a design that includes a cylindrical body section with an air inlet and a dome section for securing the swirler device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If increased cooling flows are used to improve cooling of the fuel injector shroud, then temperature control is improved, but the stoichiometry of the RQL combustion process is interfered with
Solution Approach 1:
The cooling flow is segmented into multiple separate cooling passages within the fuel injector shroud, allowing distributed cooling across different surfaces and zones. This segmentation enables effective temperature control while using less total cooling air, thereby preserving combustion stoichiometry.
Solution Approach 2:
Different regions of the fuel injector shroud are provided with customized cooling arrangements based on their specific thermal requirements. High-heat-flux areas receive enhanced cooling while lower-heat-flux areas receive minimal cooling, optimizing thermal management efficiency and reducing overall cooling air demand.
2Ease of manufacture
If conventional fuel injector shroud design is used, then manufacturing is simple, but durability under high temperature and thermal stress is reduced
Solution Approach 1:
The shroud design incorporates varying wall thicknesses and material properties in different regions to optimize thermal stress distribution. Thicker sections are placed in high-stress areas while maintaining thin walls in low-stress areas, improving durability without significantly increasing manufacturing complexity.
3Device complexity
If conventional fuel injector shroud design is used, then structure is simple, but airflow conditioning characteristics are insufficient
Solution Approach 1:
The shroud incorporates three-dimensional internal passages and surface features that condition the airflow in multiple dimensions. These geometric features create controlled turbulence and flow patterns that improve mixing without requiring additional external airflow control devices.
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 effectively reduces NOx emissions and improves the durability and airflow conditioning of fuel injector shrouds, enhancing the combustion process and reducing thermal stresses, thereby improving the overall performance of gas turbine engines.
Implementation Method 1
at least one interior rib positioned on an interior surface of the dome section configured to direct the flow of air to the swirler holes of the swirler device such that the flow of air exiting through the swirler is mixed with the flow of fuel exiting the nozzle
Implementation Method 2
a swirler device defining a center opening proximate to the nozzle of the fuel injector and a plurality of swirler holes surrounding the center opening
Data Source
Figure 1
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AI summary
A fuel injector assembly (230) includes a fuel injector (310) and a fuel injector shroud (330) housing the fuel injector. The fuel injector includes a body (314) and a nozzle (316) coupled to the body. The fuel injector shroud includes a swirler device (370) defining a center opening (372) proximate to the nozzle of the fuel injector and a plurality of swirler holes (374) surrounding the center opening, a body section (350) with an air inlet (356) configured to admit a flow of air into the fuel injector shroud and a dome section (354) defining a mount for securing the swirler device to the body section, and at least one interior rib (561) positioned on an interior surface of the dome section configured to direct the flow of air to the swirler holes of the swirler device such that the flow of air exiting through the swirler is mixed with the flow of fuel exiting the nozzle.