Gas Turbine Stator Assembly Cooling Channel Design

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Solution Overview

Problem

Current stator assemblies in gas turbines require high amounts of sealing air to prevent hot gas ingestion, which is inefficient and costly, and often involve complex geometries or expensive materials.

Innovation Solution

A stator assembly with an annular groove and radially arranged stator vanes that define an annular cooling channel, featuring primary and secondary cooling holes and baffles to direct cooling air and deflect ingested hot gas, reducing the need for sealing air and enhancing thermal protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If high amounts of sealing air are introduced in inter-assembly cavities to prevent hot gas ingestion, then thermal protection is improved, but energy efficiency deteriorates due to increased air consumption

Engineering Contradiction:
Improvehot gas ingestionVSAvoidsealing air consumption
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The stator vane is divided into multiple functional zones: a first portion with a first material having high thermal resistance for thermal insulation, and a second portion with a second material optimized for mechanical strength. This segmentation allows each zone to perform its specific function efficiently, reducing the need for excessive sealing air while maintaining thermal protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different materials are applied to different portions of the stator vane based on local requirements. The first portion exposed to hot gas uses a material with high thermal resistance properties, while the second portion uses a material optimized for mechanical strength. This local differentiation optimizes both thermal protection and structural integrity without requiring uniform over-protection throughout the entire component.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If advanced materials and complex geometries are adopted to minimize sealing air, then thermal protection is improved, but device complexity increases

Engineering Contradiction:
Improvehot gas ingestionVSAvoidstator assembly geometry
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The stator vane is segmented into two distinct portions along the axial direction, with each portion having different material properties optimized for its specific functional requirements. This segmentation provides an effective solution to thermal protection without requiring overly complex geometries, as the division is simple and straightforward along the axial axis.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention applies the local quality principle by using different materials in different portions of the stator vane. The first portion uses a material with high thermal resistance to protect against hot gas, while the second portion uses a material with optimized mechanical strength. This approach achieves effective thermal protection with a relatively simple geometric configuration, avoiding the need for complex geometries.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If uniform material properties are used throughout the stator vane, then manufacturing is simplified, but thermal protection efficiency deteriorates

Engineering Contradiction:
Improvestator vane fabricationVSAvoidthermal damage
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The stator vane is segmented into two portions with different material properties. The first portion uses a material with high thermal resistance to protect against hot gas ingestion, while the second portion uses a material optimized for mechanical strength. This segmentation improves thermal protection efficiency without significantly complicating manufacturing, as the division is straightforward along the axial direction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention implements local quality by selecting different materials for different portions of the stator vane based on their specific functional requirements. The first portion exposed to hot gas uses a material with high thermal resistance, while the second portion uses a material with optimized mechanical strength. This approach enhances thermal protection efficiency while maintaining reasonable manufacturing simplicity.

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 minimizes sealing air consumption, improves thermal integrity, and enhances engine performance by efficiently managing hot gas ingestion within the inter-assembly cavities.

Implementation Method 1

the leading edge flange being provided, on the leading edge surface, with at least one primary cooling hole in fluid communication with the annular cooling channel

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

the primary baffle deflects the flow of hot gas air ingested outside the zone comprising the primary radial gap

Methodology Applied
Scientific EffectFlow deflection:

Data Source

PatentEP3663522B1Stator assembly for a gas turbine and gas turbine comprising said stator assembly
Publication Date: 2021.11.24 ANSALDO ENERGIA SPA
  • EP3663522B1 patent drawingFigure 1
  • EP3663522B1 patent drawingFigure 2
  • EP3663522B1 patent drawingFigure 3

AI summary

A stator assembly (22) for a gas turbine comprising: a stator ring (24), which extends about a longitudinal axis (A) and comprises an outer edge (29) provided with an annular groove (30); the annular groove (30) defining a leading edge wall (34) and a trailing edge wall (35); the leading edge wall (34) being provided with an annular leading edge radial face (56) and with an annular leading edge axial face (57); a plurality of stator vanes (25) radially arranged and coupled alongside one another to the outer edge (29) of the stator ring (24) so as to close the annular grove (30) and define an annular cooling channel (32); each stator vane (25) comprises an airfoil (38), an outer shroud (39) and an inner shroud (40) coupled to the stator ring (24); the inner shroud (40) comprising a platform (42) and a leading edge flange (43) and a trailing edge flange (44) extending radially inward from the platform (42); the leading edge flange (43) being coupled to the leading edge wall (34) and the trailing edge flange (44) being coupled to the trailing edge wall (35); the leading edge flange (43) being coupled to the leading edge wall (34) so as to leave a primary radial gap (48) between the leading edge wall (34) and the platform (42) and define a leading edge surface (50) of the leading edge flange (43); the leading edge flange (43) being provided, on the leading edge surface (50), with at least one primary cooling hole (55) in fluid communication with the annular cooling channel (32); the leading edge wall (34) comprising a primary baffle (59) protruding radially from the annular leading edge axial face (57) and axially facing the at least one primary cooling hole (55) .