Gas Turbine Ring Segment Cooling via Shield Plate and Air Curtain
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Solution Overview
Problem
Gas turbines face challenges in maintaining cooling efficiency and preventing leakage of high-temperature and high-pressure combustion gas, leading to potential damage and reduced efficiency due to thermal loads on ring segments.
Innovation Solution
The design incorporates a ring segment with a shield plate, hooks, cavities, first and second cooling passages, and additional cooling passages and outlets, which direct cooling air to face both turbine vanes and adjacent ring segments, forming an air curtain to block gas leakage and enhance cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ring segments are installed in the turbine to prevent combustion gas leakage, then gas turbine efficiency is improved, but the ring segments are exposed to high thermal load and may be damaged
Solution Approach 1:
A shield plate is introduced as an intermediary component between the combustion gas and the ring segment. The shield plate faces the combustion gas and protects the ring segment from direct thermal exposure, while still allowing the ring segment to perform its gas sealing function. This mediator structure reduces the thermal load on the ring segment without compromising the gas turbine efficiency.
Solution Approach 2:
The ring segment structure is divided into multiple functional parts: the ring segment itself for gas sealing, and a separate shield plate for thermal protection. This segmentation allows each component to perform its specific function optimally - the ring segment maintains gas tightness while the shield plate handles thermal exposure, resolving the contradiction between efficiency and thermal damage risk.
2Object-affected harmful factors
If cooling passages are added to the ring segment to prevent thermal damage, then thermal load resistance is improved, but the device complexity increases
Solution Approach 1:
Instead of making the ring segment itself more complex with internal cooling passages, a separate shield plate is introduced as a mediator. The shield plate can be provided with cooling passages or other cooling structures, protecting the ring segment without increasing the complexity of the ring segment's primary sealing function. This separates the cooling function from the sealing function.
Solution Approach 2:
The cooling function is segmented from the ring segment structure and assigned to the shield plate. This allows the ring segment to remain relatively simple in structure while the shield plate handles the thermal management, reducing the overall device complexity compared to integrating cooling passages directly into the ring segment.
3Temperature
If multiple cooling passages are configured to extend in different directions, then cooling efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The shield plate serves as a mediator that can incorporate cooling passages with standardized configurations. By placing the complex cooling passage structure in the shield plate rather than the ring segment, the manufacturing precision requirements are isolated to a separate component that can be manufactured and tested independently, then assembled with the ring segment.
Solution Approach 2:
The multi-directional cooling passages are segmented into the shield plate structure rather than the ring segment. This allows the cooling passages to be configured in the shield plate with appropriate precision, while the ring segment maintains its primary sealing function with simpler manufacturing requirements. The segmentation separates the high-precision cooling function from the sealing function.
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 improves cooling efficiency, prevents ring segment damage from thermal loads, and minimizes gas turbine efficiency deterioration by effectively blocking high-temperature and high-pressure gas leakage between ring segments.
Implementation Method 1
a plurality of first cooling passages configured to connect the cavity and first side surfaces facing each other of the shield plate, and a plurality of second cooling passages configured to connect the cavity and second side surfaces facing each other of the shield plate
Implementation Method 2
direct cooling air to face both turbine vanes and adjacent ring segments, forming an air curtain to block gas leakage
Data Source
AI summary
A ring segment having improved cooling efficiency is provided. The ring segment may include a shield plate mounted to a casing which accommodates a turbine and configured to face an inner wall of the casing, a pair of hooks configured to protrude from the shield plate toward the casing to be coupled to the casing, a cavity defined between the shield plate and the pair of hooks, a plurality of first cooling passages configured to connect the cavity and first side surfaces facing each other of the shield plate, and a plurality of second cooling passages configured to connect the cavity and second side surfaces facing each other of the shield plate, wherein the first cooling passages extend in a longitudinal direction of a central axis of the turbine, and the second cooling passages extend in a circumferential direction of the turbine.