Gas Turbine Flow Passage Plate Ledge Cooling Design
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Solution Overview
Problem
The increased temperature of combustion gas in gas turbines poses a challenge in enhancing the cooling effect of cooling air on flow passage forming plates, as existing cooling methods struggle to effectively cool regions near the leading edge and suction-side surfaces of vanes due to space constraints and heat transfer inefficiencies.
Innovation Solution
The flow passage forming plate design incorporates a ledge along only a part of its inner wall surface, allowing for closer placement of through-holes in the impingement plate, which enhances cooling by directing cooling air into an inner cavity and reducing the thickness of the plate in areas without ledges, thereby improving heat transfer and cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is blown through through-holes in the impingement plate toward the inner surface of the shroud plate main body, then the shroud plate main body is impingement-cooled, but the cooling effect is insufficient in regions near the leading edge and suction-side surfaces due to space constraints and heat transfer inefficiencies
Solution Approach 1:
The peripheral wall is segmented into multiple regions: a first region with a ledge providing impingement cooling, a second region without ledge allowing reduced plate thickness for enhanced cooling, and a third region with ledge for additional impingement cooling. This segmentation allows different cooling strategies to be applied to different regions of the flow passage forming plate, optimizing overall cooling effectiveness while managing thermal stresses.
Solution Approach 2:
Different regions of the flow passage forming plate are given different local structures: the first region has a ledge for impingement cooling, the second region has reduced thickness for enhanced heat transfer, and the third region has ledge for additional cooling. This local differentiation optimizes cooling effectiveness in each specific region based on its thermal requirements and structural constraints.
2Temperature
If the plate thickness is reduced in areas without ledges to improve heat transfer, then cooling efficiency is enhanced, but the structural strength and stability of the plate may be compromised
Solution Approach 1:
The plate is divided into multiple regions with different thicknesses and cooling structures. The second region has reduced thickness for enhanced heat transfer, while the first and third regions have full thickness with ledges for impingement cooling and structural support. This segmentation allows the plate to achieve both high heat transfer efficiency and adequate structural strength by optimizing each region's properties according to its specific requirements.
Solution Approach 2:
Different regions of the plate have different local properties: the second region has reduced thickness for enhanced heat transfer, while the first and third regions have full thickness with ledges for structural support and impingement cooling. This local differentiation allows the plate to simultaneously achieve high cooling efficiency in critical regions and maintain adequate overall structural integrity.
3Power
If combustion gas temperature is raised to enhance output efficiency, then power generation efficiency improves, but the cooling requirements of flow passage forming plates increase significantly
Solution Approach 1:
The cooling system is segmented into multiple regions with different cooling mechanisms: impingement cooling in the first and third regions, and enhanced conduction cooling through reduced thickness in the second region. This segmentation allows the system to handle higher combustion gas temperatures by providing targeted cooling in different areas, enabling the gas turbine to operate at higher temperatures for improved output efficiency while maintaining plate integrity.
Solution Approach 2:
Different regions of the plate have different local cooling properties optimized for their specific thermal loads: the first and third regions have ledges for impingement cooling to handle high heat flux areas, while the second region has reduced thickness for enhanced heat conduction. This local optimization allows the system to manage higher combustion gas temperatures effectively, enabling improved power output while maintaining reliable cooling of all plate regions.
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 enhances the cooling effect on flow passage forming plates by improving heat transfer and reducing temperature, particularly in regions difficult to cool, such as near the leading edge and suction-side surfaces, leading to improved performance and efficiency in gas turbines.
Implementation Method 1
Cooling air is blown out of the plurality of through-holes of the impingement plate toward the inner surface of the shroud plate main body. Thus, the shroud plate main body having the gas path surface is impingement-cooled by this cooling air.
Implementation Method 2
the wall between the inner cavity and an outer space on the opposite side based on that part has a smaller thickness, so that, compared with the part where the ledge is provided, cooling of the plate main body having the gas path surface is promoted and the temperature of the gas path surface can be reduced
Data Source
AI summary
A flow passage forming plate includes a plate main body, a peripheral wall, and a ledge. The plate main body has a gas path surface facing a side of a gas flow passage, and an inner surface facing the opposite side from the gas path surface. The peripheral wall protrudes along a peripheral edge of the plate main body, from the inner surface toward an opposite-flow-passage side. The ledge protrudes along an inner wall surface of the peripheral wall, from the inner surface toward the opposite-flow-passage side. The ledge receives an impingement plate having a plurality of through-holes. The ledge is disposed only in a part of an inner wall surface of the peripheral wall.