Turbine Stator Vane Asymmetric Cooling for Inner Shroud Temperature
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Solution Overview
Problem
The metal temperature of the inner shroud in turbine stator vanes is lower than the assumed temperature, leading to reduced efficiency in gas turbines.
Innovation Solution
The turbine stator vane design includes an inner shroud with a first recessed portion and an outer shroud with a second recessed portion, where the number of outer passages exceeds the number of inner passages, optimizing the cooling distribution to match the assumed metal temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the inner shroud is cooled with cooling air through inner passages, then the metal temperature of the inner shroud is reduced, but the temperature becomes lower than the assumed temperature, reducing turbine efficiency
Solution Approach 1:
The patent applies local quality by creating asymmetric cooling configurations: the outer shroud has multiple outer passages while the inner shroud has fewer inner passages. This local differentiation in cooling intensity allows the outer shroud to be cooled more while the inner shroud maintains higher temperature, optimizing overall turbine efficiency by preventing excessive cooling of the inner shroud.
Solution Approach 2:
The patent employs asymmetry by deliberately designing an unequal number of cooling passages between the outer and inner shrouds. The outer shroud contains a greater number of outer passages compared to the number of inner passages in the inner shroud, creating an asymmetric cooling distribution that matches the thermal requirements of different shroud regions and prevents the inner shroud temperature from dropping below the assumed temperature.
2Temperature
If cooling air is supplied to both inner and outer shrouds, then both components are cooled, but the cooling distribution is unoptimized leading to excessive cooling of the inner shroud
Solution Approach 1:
The patent implements local quality by differentiating the cooling passage configuration in different regions: the outer shroud is equipped with multiple outer passages for adequate cooling, while the inner shroud has fewer inner passages to prevent over-cooling. This localized quality adjustment optimizes the temperature distribution across the turbine stator vane components.
Solution Approach 2:
The patent applies partial action by providing cooling passages selectively - the outer shroud receives more extensive cooling through multiple outer passages, while the inner shroud receives partial cooling through fewer inner passages. This partial cooling approach to the inner shroud prevents excessive temperature reduction, maintaining it close to the assumed temperature for optimal turbine efficiency.
3Temperature
If the number of inner passages equals the number of outer passages, then cooling is uniformly distributed, but the inner shroud becomes excessively cooled reducing turbine efficiency
Solution Approach 1:
The patent applies asymmetry by deliberately creating an unequal distribution of cooling passages: the outer shroud has multiple outer passages while the inner shroud has fewer inner passages. This asymmetric configuration ensures that the inner shroud is not excessively cooled, maintaining its temperature close to the assumed temperature for optimal turbine efficiency.
Solution Approach 2:
The patent implements local quality by differentiating the cooling intensity in different shroud regions. The outer shroud receives more intensive cooling through multiple passages, while the inner shroud receives less intensive cooling through fewer passages. This local quality adjustment prevents uniform over-cooling and maintains the inner shroud temperature at an optimal level.
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 optimizes the cooling of the turbine stator vane, improving turbine efficiency by suppressing excessive cooling of the inner shroud and maintaining the metal temperature closer to the assumed level.
Implementation Method 1
a stator vane body (airfoil portion), an inner shroud, and an outer shroud are respectively cooled with cooling air
Implementation Method 2
the temperature of the combustion gas on the hub side was lower than a predetermined assumption, and it was found that the metal temperature of the inner shroud was also lower than the predetermined assumption
Data Source
AI summary
A turbine stator vane according to at least one embodiment of the present disclosure comprises an airfoil, an inner shroud provided on the inner-peripheral side of the airfoil, and an outer shroud provided on the outer-peripheral side of the airfoil. The inner shroud has a first recess formed in the surface on the side opposite the airfoil across a gas path surface of the inner shroud. The outer shroud has a second recess formed in the surface on the side opposite the airfoil across a gas path surface of the outer shroud, and at least one outer passage that communicates with the second recess and does not communicate with the space inside the airfoil. The number of outer passages is greater than the number of inner passages that communicate with the first recess in the inner shroud and do not communicate with the space inside the airfoil.