Turbine Vane Shroud Cooling Passages for Lower Air Use
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Solution Overview
Problem
The challenge is to effectively cool turbine vanes in gas turbines while minimizing the usage of cooling air and enhancing durability.
Innovation Solution
The turbine vane design incorporates a shroud with multiple air passages, including first and second air passages, which direct cooling air to convectively cool the upstream portion and purge the combustion gas, reducing heat transfer and air usage. These passages are strategically located to optimize cooling efficiency and durability by controlling the flow of cooling air and combustion gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single cooling air passage is used to cool the turbine vane, then the structure is simple, but the cooling effectiveness is insufficient and the usage amount of cooling air is high
Solution Approach 1:
The single cooling air passage is divided into multiple separate air passages (first air passage and second air passage) with different functions. The first air passage is dedicated to convectively cooling the gas path surface, while the second air passage is dedicated to purging combustion gas from the front end surface region. This segmentation allows each passage to be optimized for its specific function, improving overall cooling effectiveness without requiring excessive cooling air.
Solution Approach 2:
Different regions of the turbine vane are provided with specialized cooling passages tailored to their specific thermal requirements. The first air passage targets the gas path surface which experiences direct combustion gas exposure, while the second air passage targets the front end surface region which is susceptible to combustion gas intrusion. This localized approach ensures efficient cooling where most needed while reducing overall cooling air consumption.
2Temperature
If cooling air flows directly over the gas path surface, then cooling is effective, but combustion gas may intrude into the front end surface region
Solution Approach 1:
The second air passage acts as an intermediary system that introduces cooling air specifically to the front end surface region to create a protective barrier against combustion gas intrusion. This intermediary cooling flow prevents combustion gas from reaching the front end surface while the first air passage simultaneously cools the gas path surface, resolving the conflict between effective cooling and preventing combustion gas intrusion.
Solution Approach 2:
The second air passage provides preliminary cooling action to the front end surface region before combustion gas can intrude into this area. By establishing a cooling air barrier in advance, the system prevents combustion gas intrusion proactively rather than reacting to it after occurrence, thereby protecting the front end surface from thermal damage.
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 cools the turbine vane, reduces the amount of cooling air required, and improves durability by efficiently managing heat transfer and gas flow, thereby enhancing the overall performance of the gas turbine.
Implementation Method 1
The cooling air flowing into the first air passage convection-cools the upstream portion of the shroud and particularly the upstream portion of the gas path surface
Implementation Method 2
The cooling air flowing into the second air passage convection-cools the front end surface region
Implementation Method 3
The cooling air flowing out into the combustion gas flow path suppresses the front end corner portion from being heated by the combustion gas by suppressing the heat transfer from the combustion gas to the front end corner portion
Data Source
AI summary
A turbine vane includes a blade body and a shroud. The shroud includes a gas path surface, a front end surface, a front end corner portion which is a corner portion between the gas path surface and the front end surface, a cavity defining surface which defines a cavity allowing cooling air to flow thereinto, a first air passage in which the cooling air flows, and a second air passage in which the cooling air flows. The first air passage includes a first inlet opened at the cavity defining surface and a first outlet opened at the front end corner portion. The second air passage includes a second inlet opened at the cavity defining surface and a second outlet opened at the front end surface.