Gas Turbine Ring Segment Cooling Channel Design
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Solution Overview
Problem
Conventional ring segments in gas turbines require significant cooling air extracted from compressed air, leading to reduced efficiency and performance degradation due to inadequate cooling of high-temperature regions.
Innovation Solution
The ring segment design incorporates a main cavity for cooling air intake, with first and second cooling channels extending along the axial direction and third cooling channels along the circumferential direction, effectively directing cooling air to high-temperature regions through convective and impingement cooling, and includes additional cooling channels and structures to enhance cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a large amount of cooling air is extracted from compressed air to sufficiently cool the ring segment, then the cooling effectiveness is improved, but the gas turbine efficiency is reduced and performance is degraded
Solution Approach 1:
The patent applies local quality by providing different cooling channel configurations at different locations of the ring segment. Specifically, the first cooling channels are provided at both upstream and downstream ends along the rotational axis, while the second cooling channels are provided at the upstream end in the rotation direction. This localized cooling approach directs cooling air to high-temperature regions, improving cooling effectiveness without requiring excessive cooling air extraction that would degrade overall turbine efficiency.
Solution Approach 2:
The ring segment is divided into multiple segments with independent cooling channel systems. Each segment body has its own set of cooling channels (first, second, and third cooling channels) that can be independently configured and controlled. This segmentation allows for optimized cooling air distribution to specific high-temperature zones without uniformly cooling the entire ring segment, thereby reducing the total cooling air requirement and maintaining gas turbine efficiency.
2Device complexity
If conventional cooling channels extending along the rotational axis are used, then the structure is simple, but high-temperature regions are not effectively cooled
Solution Approach 1:
The patent enhances cooling effectiveness by implementing local quality through strategically positioned cooling channels. The first cooling channels extend along the rotational axis at both upstream and downstream ends, while the second cooling channels are specifically positioned at the upstream end in the rotation direction. This configuration ensures that high-temperature regions receive targeted cooling, improving thermal management without excessive structural complexity.
Solution Approach 2:
The patent introduces cooling channels in multiple dimensions and orientations. In addition to the axial cooling channels (first cooling channels), cooling channels are provided in the rotational direction (second cooling channels) and circumferential directions (third cooling channels). This multi-dimensional cooling approach effectively reaches high-temperature regions that would be inaccessible with single-directional cooling channels, thereby improving cooling effectiveness without overly complicating the structure.
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 intensively cools high-temperature regions of the ring segment, reducing the amount of cooling air needed from the compressor and preventing performance degradation by optimizing the use of cooling air for effective convective and direct cooling.
Implementation Method 1
An impingement plate has a plurality of small holes, through which cooling air is blown out toward the segment body to perform impingement cooling on the segment body
Implementation Method 2
the segment body is provided with a plurality of cooling channels along the combustion gas flow direction, and the cooling air having performed impingement cooling flows through these cooling channels to perform convective cooling on the segment body
Data Source
AI summary
A ring segment includes segment bodies arranged along a circumferential direction; a main cavity; first cooling channels inside the segment body to extend along an axial direction of a rotor and arrayed in the circumferential direction, and whose ends communicate with the main cavity on an upstream side thereof; a second cooling channel inside the segment body on an upstream side in a rotation direction of the rotor to extend along the axial direction, and whose first end communicates with the main cavity on the upstream side thereof; and third cooling channels to extend along the circumferential direction, in a predetermined region forming a part of a lateral end of the segment body on the upstream side and stretching from an end of the segment body on a downstream side in the combustion gas flow direction toward the upstream side, and whose first ends communicate with the second cooling channel.