Flare-less Seal Slots for Combustor Cooling
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Solution Overview
Problem
Conventional seals in gas turbine combustors fail to provide sufficient cooling, leading to deterioration, premature erosion, and increased emissions due to inadequate impingement cooling and oxidation, which affects the fuel injector and combustion chamber performance.
Innovation Solution
A flare-less seal design with full-length slots on the inner surface for enhanced convective heat transfer and radial pressure distribution, allowing effective cooling of both the seal and fuel injector, and controlling the fuel spray cone angle to reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional seals with flared portions and cooling apertures are used, then cooling of the seal is provided, but the cooling is insufficient leading to deterioration, melting, and burn-back of the flared portion
Solution Approach 1:
The seal is divided into multiple functional zones: a first region with a first cooling aperture for cooling the seal body, and a second region with a second cooling aperture for cooling the fuel injector. This segmentation allows targeted cooling of different components, preventing the insufficient cooling that caused deterioration in conventional single-aperture designs.
Solution Approach 2:
Different cooling strategies are applied to different locations: the first cooling aperture provides cooling to the seal body while the second cooling aperture provides cooling to the fuel injector. The flared portion is eliminated entirely, replacing it with localized cooling apertures positioned to deliver cooling fluid directly to critical heat zones, ensuring adequate temperature control without material degradation.
2Temperature
If cooling fluid is directed angularly through cooling apertures for impingement cooling, then cooling of the flared portion is attempted, but the leakage flow between seal and fuel injector closes-off during operation making secondary cooling ineffective
Solution Approach 1:
The cooling system is segmented into two independent cooling pathways: a first cooling aperture for the seal body and a second cooling aperture for the fuel injector. This ensures that each component receives dedicated cooling flow that cannot be compromised by the other, maintaining effective cooling throughout operation even when pressure conditions change.
Solution Approach 2:
The problematic flared portion that caused leakage flow closure is completely removed from the design. The second cooling aperture is positioned to cool the fuel injector directly without relying on leakage flow through a flared portion, ensuring continuous effective cooling of the fuel injector throughout operation.
3Reliability
If conventional seals are used, then sealing function is provided, but insufficient cooling causes oxidation of the seal and erosion of the fuel injector tip
Solution Approach 1:
The seal structure is segmented into distinct regions with dedicated cooling functions. The first cooling aperture protects the seal body from oxidation by maintaining lower temperatures, while the second cooling aperture protects the fuel injector from erosion and overheating. This segmented approach ensures both components are protected from harmful thermal effects throughout their service life.
Solution Approach 2:
Cooling is provided proactively before damage can occur. The cooling apertures are positioned and sized to deliver adequate cooling fluid flow that prevents temperature rise to levels that would cause oxidation or erosion, protecting the components throughout their intended service life rather than attempting to address damage after it occurs.
4Temperature
If cooling apertures are designed to cool both seal and fuel injector, then integrated cooling is attempted, but the cooling fluid adversely affects the fuel and air mixture supplied by the fuel injector
Solution Approach 1:
The cooling system is segmented into separate cooling zones: the first cooling aperture delivers cooling fluid to the seal body, and the second cooling aperture delivers cooling fluid to the fuel injector. This segmentation ensures that cooling fluid is applied where needed without interfering with the fuel spray pattern or combustion process, avoiding the emission problems caused by cooling fluid mixing with the fuel-air mixture.
Solution Approach 2:
Cooling is applied locally to specific components (seal body and fuel injector) rather than in a position that would allow cooling fluid to mix with the fuel spray. The second cooling aperture is positioned to cool the fuel injector body without directing cooling fluid into the fuel spray cone, maintaining proper combustion conditions while providing effective cooling.
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 new seal design improves durability and reduces smoke emissions by providing efficient cooling and controlling combustion processes, addressing issues of seal durability and engine emissions while being compact and adaptable for existing combustor arrangements.
Implementation Method 1
a cooling fluid flowing through the substantially full-length slots may allow cooling of the seal and the fuel injector
Implementation Method 2
a placement of the slots on the inner surface may also generate a radial positive pressure at an interface between the seal and the outer diameter of the fuel injector
Data Source
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AI summary
A combustor arrangement (100) includes a fuel injector (114), and a seal (200, 1300) arranged around the fuel injector (114) and having an upstream end (202, 1302) and a downstream end (204, 1304). The seal (200, 1300) includes an annular body (206, 1306) at least partially abutting the fuel injector (114). The annular body (206, 1306) includes an inner surface (212, 1312) facing the fuel injector (114) and an outer surface (210, 1310) radially spaced apart from the inner surface (212, 1312) relative to the central axis (A1, A4). The annular body (206, 1306) further includes a plurality of slots (214, 1314) disposed on the inner surface (212, 1312) and circumferentially spaced apart from each other relative to the central axis (A1, A4). Each slot (214, 1314) axially extends at least partially from the downstream end (204, 1304) to the upstream end (202, 1302). Each slot (214, 1314) is disposed in fluid contact with the fuel injector (114). The seal (200, 1300) also includes a flange (208, 1308) radially extending from the outer surface (210, 1310) of the annular body (206, 1306) at the upstream end (202, 1302).