Turbine Blade Cooling Air Reduction via Nested Insert
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Solution Overview
Problem
Existing turbine blade designs require increased cooling air flow, leading to larger flow passage cross-sectional areas and reduced gas turbine performance due to low-temperature air being blown out through film cooling holes, which decreases heat efficiency.
Innovation Solution
A turbine blade design featuring plate-like ribs forming cavities with hollow inserts and impingement cooling holes, where cooling air is reused to impingement-cool both the ventral and dorsal sides of the blade main body before being blown out through film cooling holes, reducing the total amount of cooling air and preventing low-temperature air from escaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wall surface of an insert is disposed such that impingement holes are located as close as possible to the inner wall surface of the blade main body, then impingement cooling effectiveness is improved, but the flow passage cross-sectional area of the insert is increased, thus increasing the amount of cooling air required
Solution Approach 1:
The hollow insert is nested within the blade main body cavity, with the insert's outer circumferential surface positioned away from the inner circumferential surface of the blade main body. This nesting arrangement creates a cooling space between the insert and blade main body, allowing cooling air to flow through this space and reach the inner wall surface for effective cooling without requiring the insert wall to be positioned immediately adjacent to the blade inner surface.
Solution Approach 2:
The invention introduces a spatial dimension by creating a cooling space between the insert and the blade main body. Instead of positioning impingement holes directly at the inner wall surface (zero-dimensional contact), the cooling air flows through a three-dimensional cooling space, allowing effective cooling while maintaining a smaller insert cross-sectional area and reducing cooling air consumption.
2Device complexity
If all cooling air introduced to the inside of the insert performs impingement-cooling only once and flows out through film cooling holes, then the cooling process is simple, but low-temperature cooling air is blown out through the film cooling holes, thus reducing the gas temperature and heat efficiency
Solution Approach 1:
The cooling air that exits the insert through the outer circumferential surface does not immediately leave the blade through film cooling holes. Instead, it continues to flow through the cooling space and performs a second impingement cooling action on the blade inner wall surface. This continuous useful action ensures that the cooling air maintains its cooling capability longer and does not escape as low-temperature air through film cooling holes, thereby preserving heat efficiency.
Solution Approach 2:
The cooling air is pre-cooled as it flows through the cooling space between the insert and the blade main body before reaching the inner wall surface for the second impingement cooling. This preliminary cooling action in the cooling space prepares the air for effective secondary cooling, preventing it from becoming low-temperature air that would reduce heat efficiency if discharged through film cooling holes.
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 reduces cooling air consumption by approximately 10% and prevents low-temperature air from being blown out through film cooling holes, thereby enhancing gas turbine performance and heat efficiency.
Implementation Method 1
part of a cooling medium that has impingement-cooled a ventral side of the inner circumferential surface of the blade main body by passing through one of the plurality of impingement cooling holes
Implementation Method 2
impingement-cool the inner wall surface (inner circumferential surface) of a blade main body
Implementation Method 3
form a cooling space between outer circumferential surfaces of the inserts and an inner circumferential surface of the blade main body
Implementation Method 4
blown out through dorsal-side film cooling holes of the film cooling holes in the blade main body
Data Source
Figure 1
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AI summary
The amount of cooling air (cooling medium) can be reduced, and low-temperature cooling air is prevented from being blown out through film cooling holes. Part of a cooling medium impingement-cooling an inner circumferential surface (17) of a blade main body (11) located on a ventral side further impingement-cools the inner circumferential surface (17) of the blade main body (11) located on a dorsal side and is blown out through film cooling holes (13) in the blade main body (11) that are located on the dorsal side.