Turbomachine Combustor Cartridge Tip Thermal Stress Management
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Solution Overview
Problem
Existing liquid fuel cartridge tips in turbomachines are susceptible to transient and steady-state thermal stresses, which can lead to component damage over time, especially during liquid fuel operation, while maintaining multiple injection outlets and premixing functions.
Innovation Solution
The cartridge tip design incorporates a heat shield and a solid structure with increased conductive heat transfer paths, including a radially extending heat shield within the annular air passage and a circumferential rib to prevent backflow, along with integrally formed components using additive manufacturing, enhancing thermal management and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If complex geometry with multiple injection outlets and premixing chambers is used, then combustion efficiency is improved, but thermal stress susceptibility increases
Solution Approach 1:
The cartridge tip is divided into multiple functional segments including premixing chambers, injection outlets, and heat shields. Each segment performs a specific function while the overall structure maintains thermal stress resistance through strategic segmentation of thermal loads.
Solution Approach 2:
Heat shields are introduced as intermediary components between the high-temperature combustion zone and the cartridge tip structure. These heat shields mediate the thermal interaction, reducing direct thermal exposure of critical components while maintaining combustion efficiency.
2Reliability
If solid structure with increased conductive heat transfer paths is used, then thermal stress damage is reduced, but device complexity increases
Solution Approach 1:
The heat shield and structural support functions are merged into a single integrated component. The heat shield is formed as part of the cartridge tip structure, combining thermal protection with structural integrity while reducing the number of separate parts.
Solution Approach 2:
The solid structure serves multiple functions simultaneously: it provides structural support, creates conductive heat transfer paths, and forms part of the combustion geometry. This multi-functionality reduces the need for additional components.
3Temperature
If heat shield with radially extending structure is used, then thermal gradients are reduced, but manufacturing complexity increases
Solution Approach 1:
The heat shield geometry parameters are optimized to create radially extending structures that effectively manage thermal gradients. By adjusting the radial and axial dimensions of the heat shield, optimal thermal management is achieved while maintaining manufacturability.
Solution Approach 2:
The heat shield may utilize composite material construction or thermally resistant materials that combine effective heat blocking with ease of manufacture. This allows complex geometries to be produced while maintaining thermal performance.
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 design effectively reduces thermal gradients and minimizes high-stress zones, thereby extending the hardware life and maintaining efficient fuel injection and combustion performance without damage from thermal stresses.
Implementation Method 1
a solid structure with increased conductive heat transfer paths, including a radially extending heat shield within the annular air passage
Implementation Method 2
a circumferential rib to prevent backflow
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A cartridge tip (200) includes a main body (208) having an outer annular wall (210) and an inner core (212) each extending between a respective upstream end (214, 215) and a respective downstream end (216, 217). The inner core (212) is radially spaced apart from the outer annular wall (210) such that an annular air passage (217) is defined at least partially between the outer annular wall (210) and the inner core (212). A pilot fuel circuit (250) extends between a pilot inlet (254) defined in the upstream end (215) of the inner core (212) and a pilot outlet (256) defined in the downstream end (217) of the inner core (212). The pilot fuel circuit (250) extends at least partially along an axial centerline (206) of the cartridge tip (200). A main fuel circuit (252) extends between a main inlet (266) in the upstream end (215) of the inner core (212) and a plurality of main outlets (268) circumferentially spaced apart from one another and disposed upstream from the from the pilot outlet (256).