Turbine Ring Segment Cooling Channels for High Inlet Temperatures
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Solution Overview
Problem
Existing ring segments in turbomachines face challenges in effectively cooling adjacent surfaces due to increased inlet temperatures, leading to difficulty in maintaining structural integrity and efficiency.
Innovation Solution
A ring segment design with a double-stage cooling system, incorporating cooling channels and auxiliary cavities, which includes first and second auxiliary cavities and channels, provides comprehensive cooling through impingement and secondary impingement methods to effectively cool both inner and outer surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple cooling structure with direct air introduction is used, then the device complexity is reduced, but the cooling efficiency deteriorates due to increased inlet temperatures
Solution Approach 1:
The cooling system is divided into multiple independent cooling channels (first cooling channel, second cooling channel, third cooling channel, fourth cooling channel) that separately target different surfaces of the ring segment. This segmentation allows each channel to be optimized for its specific cooling task, improving overall cooling efficiency without requiring a completely complex integrated system.
Solution Approach 2:
Different cooling strategies are applied to different locations of the ring segment. The first and second cooling channels cool the inner surface where combustion gas contacts, while the third and fourth cooling channels cool the outer surface adjacent to other ring segments. This local differentiation ensures that each area receives appropriate cooling based on its thermal exposure.
2Temperature
If cooling channels are added to cool the ring segment, then the temperature control is improved, but the device complexity increases
Solution Approach 1:
Multiple cooling functions are merged into a single ring segment structure. The cooling channels are integrated directly into the ring segment body, combining the cooling system with the structural component. This merging reduces the need for separate external cooling systems and minimizes overall device complexity while maintaining effective temperature control.
Solution Approach 2:
The ring segment structure serves multiple functions simultaneously: it provides structural support for the turbine, prevents combustion gas leakage, and incorporates integrated cooling channels for thermal management. This multi-functionality eliminates the need for separate dedicated cooling components, reducing overall system complexity.
3Productivity
If the inlet temperature of the turbine is increased to improve efficiency, then the power generation efficiency is improved, but the cooling effectiveness of the ring segment deteriorates
Solution Approach 1:
Cooling air is introduced into the cooling channels before the high-temperature combustion gas reaches the ring segment surfaces. This preliminary cooling action establishes a protective thermal barrier in advance, allowing the turbine to operate at higher inlet temperatures without compromising ring segment temperature control.
Solution Approach 2:
The high-temperature combustion gas that would otherwise damage the ring segment is converted into a beneficial cooling mechanism. The temperature differential between the combustion gas and cooling air creates efficient heat transfer, and the controlled thermal exposure actually enhances the cooling effect by maintaining larger temperature gradients for heat dissipation.
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 enhances cooling efficiency by utilizing double-stage cooling, effectively managing high temperatures and preventing damage to adjacent ring segments, thereby improving the overall performance and longevity of the turbomachine.
Implementation Method 1
a cooling channel through which cooling air flows
Implementation Method 2
cooling air flows through the cooling channel
Implementation Method 3
protrude toward an inner circumferential surface of the turbine casing to form a first auxiliary cavity and a second auxiliary cavity at both ends in a flow direction of fluid, and a plurality of auxiliary channels extending in a direction crossing the cooling channel to connect the first auxiliary cavity and the second auxiliary cavity with each other
Data Source
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AI summary
A ring segment and a turbomachine including the ring segment are provided. The ring segment installed on an inner circumferential surface of a casing and disposed to face an end of a blade existing inside the casing, the ring segment includes a segment body disposed inside the casing in a radial direction of the casing and having a channel through which cooling air flows, and a pair of segment protrusions protruding outward from the segment body, coupled to the inner circumferential surface of the casing, and spaced apart from each other along a flow direction of fluid flowing through the casing to form an RS cavity through which cooling air flows, wherein the segment body includes a cavity for supplying cooling air introduced from the RS cavity to the channel.