Gas Turbine Stator Vane Cooling via Localized Shelves

Solution Overview

Problem

Stator blades in gas turbines face increased thermal stress due to enhanced rigidity, which can lead to thermal deformation and strain, particularly in the shroud components exposed to high-temperature combustion gases.

Innovation Solution

The stator blade design incorporates a shroud with a bottom plate, peripheral wall, shelf, and partition ribs, featuring an impingement plate with through-holes, to create a cavity and improve cooling efficiency, while reducing thermal stress by selectively omitting shelves at specific regions where partition ribs join the blade body and peripheral walls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the rigidity of the stator blade is increased to prevent thermal deformation, then the structural stability is improved, but the thermal stress partially increases

Engineering Contradiction:

Improvestructural stabilityVSAvoidthermal stress

Core Design Contradiction:

Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The invention applies local quality by selectively forming shelves at specific positions on the inner wall surface of the peripheral wall, rather than uniformly across the entire surface. The shelves are positioned at locations where cooling airflow is needed, creating localized structural reinforcement and cooling enhancement exactly where thermal stress and deformation risks are highest, while leaving other areas without unnecessary shelves that would increase overall rigidity and thermal stress.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention segments the cooling function by dividing the peripheral wall into multiple sections, with shelves formed only at specific segments rather than continuously. This segmentation allows different parts of the peripheral wall to have different structural characteristics - some areas with shelves for cooling enhancement and structural support, and other areas without shelves to maintain lower overall rigidity and reduce thermal stress accumulation.

Inventive Principle:

Principle #1Segmentation

2Use of energy by moving object

If shelves are formed along the inner wall surface of the peripheral wall to support the impingement plate, then the cooling efficiency is improved, but the rigidity of the shroud body increases leading to higher thermal stress

Engineering Contradiction:

Improvecooling efficiencyVSAvoidthermal stress

Core Design Contradiction:

Use of energy by moving objectVSStress or pressure

Solution Approach 1:

The invention applies local quality by selectively forming shelves at specific positions on the inner wall surface of the peripheral wall, rather than uniformly across the entire surface. The shelves are positioned at locations where cooling airflow is needed, creating localized structural reinforcement and cooling enhancement exactly where thermal stress and deformation risks are highest, while leaving other areas without unnecessary shelves that would increase overall rigidity and thermal stress.

Inventive Principle:

Principle #3Local quality

3Strength

If the shroud body is designed with enhanced rigidity to prevent distortion, then the structural integrity is improved, but the thermal stress generation increases

Engineering Contradiction:

Improvestructural integrityVSAvoidthermal stress

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The invention applies local quality by selectively forming shelves at specific positions on the inner wall surface of the peripheral wall, rather than uniformly across the entire surface. The shelves are positioned at locations where cooling airflow is needed, creating localized structural reinforcement and cooling enhancement exactly where thermal stress and deformation risks are highest, while leaving other areas without unnecessary shelves that would increase overall rigidity and thermal stress.

Inventive Principle:

Principle #3Local quality

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 suppresses thermal stress generation and deformation in the stator blade shroud components, enhancing the structural integrity and operational reliability of the gas turbine by optimizing cooling airflow and reducing thermal strain.

Implementation Method 1

an impingement plate attached to the shroud body and having a plurality of through-holes. The shroud body is formed to include the bottom plate, a peripheral wall protruding toward the counter-flow path side from a peripheral edge of the inner surface of the shroud body, a shelf formed along an inner wall surface of the peripheral wall, protruding to the counter-flow path side from the inner surface of the bottom plate, and supporting the impingement plate

Methodology Applied

Scientific EffectImpingement cooling: Cooling

Implementation Method 2

The impingement plate forms a cavity which is a space between the inner surface of the bottom plate and the inner wall surface of the peripheral wall

Methodology Applied

Scientific EffectConvection cooling: Convection

Data Source

PatentUS12018588B2Stator vane and gas turbine

Publication Date: 2024.06.25 MITSUBISHI HEAVY IND LTD

AI summary

This stator vane is at least provided with a blade body disposed in a combustion gas flow channel through which a combustion gas flows, a shroud that defines a part of the combustion gas flow channel, and an impingement plate attached to the shroud. A partition rib extends from a blade body end to an inner wall surface of a peripheral wall, and a shelf is provided at a rib-less part of the inner wall surface of the peripheral wall excluding at least a part in which the partition rib extends to the inner wall surface of the peripheral wall.