Gas Turbine Stator Vane Segment Thermal Stress Reduction
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Solution Overview
Problem
Gas turbines experience increased thermal stress due to operational conditions, which can shorten their lifespan.
Innovation Solution
A stator vane segment design where a first stator vane and a second stator vane are joined using a specific positioning and protrusion configuration, with the second vane positioned on one side, and protrusions on both vanes are aligned and joined, reducing the distance between surfaces to minimize thermal expansion forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If two stator vanes are joined to form a stator vane segment, then the structural integrity is improved, but thermal stress increases
Solution Approach 1:
The patent applies local quality by creating an asymmetric configuration where only the second stator vane has a protrusion portion at its first end portion, while the first stator vane has a recessed portion at its corresponding location. This localized structural modification concentrates the joining feature in a specific area, allowing the rest of the stator vane segment to maintain uniform thermal expansion characteristics, thereby reducing overall thermal stress while preserving structural integrity at the joining location.
2Strength
If protrusion portions are joined to connect stator vanes, then the connection strength is improved, but the distance between surfaces increases
Solution Approach 1:
The patent employs asymmetry by positioning the protrusion portion on the second stator vane's first end portion to extend in the radial direction toward the combustion gas flow path, creating an asymmetric configuration where the protrusion and recessed portions are offset from each other. This asymmetric arrangement allows the joining tool to engage effectively while maintaining optimal surface alignment, achieving strong connection without excessive distance between critical surfaces.
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 configuration reduces thermal stress on the stator vane segment, enhancing its resistance to low-cycle fatigue and extending its lifespan.
Implementation Method 1
a large thermal stress may act although depending on an environment in which the gas turbine is used or conditions under which the gas turbine is operated
Data Source
AI summary
This stationary blade segment includes a first stationary blade, a second stationary blade, and a connecting implement that connects the first stationary blade and the second stationary blade. A first shroud of the first stationary blade includes a first gas path face, and a first protruding part that protrudes to a reverse-channel side at a first end section of the first shroud. A second shroud of the second stationary blade includes a second gas path face, a second protruding part that protrudes to the reverse-channel side at a first end section of the second shroud, and a third protruding part that protrudes to the reverse-channel side at a second end section of the second shroud and that is connected to the first protruding part by the connecting implement.