Gas Turbine Stator Vane Sealing Ribs Reduce Friction

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Solution Overview

Problem

Existing gas turbine stator vane sealing systems face challenges in maintaining narrow passages for effective sealing while minimizing contact between stator and rotor components due to thermal expansion, which can lead to friction and damage, and known solutions are costly or require additional components.

Innovation Solution

A gas turbine stator vane design featuring an airfoil with an inner platform that includes integral aft sealing ribs delimited by parallel grooves, allowing contact only at these ribs during thermal expansion, reducing friction and damage risk without affecting sealing effectiveness, and eliminating the need for additional components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If stator and rotor components are spaced apart to maintain narrow passages for sealing airflow, then sealing effectiveness is improved, but thermal expansion causes contact between components leading to friction and damage

Engineering Contradiction:
Improvesealing effectivenessVSAvoidfriction and damage from thermal expansion contact
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sealing surface is segmented into multiple discrete sealing ribs rather than a continuous contact surface. This segmentation allows the sealing function to be maintained at specific points while minimizing overall contact area, thereby reducing friction and thermal expansion-induced damage while preserving sealing effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing ribs are strategically positioned at specific locations where sealing is most critical, rather than providing uniform contact across the entire sealing surface. This local quality approach concentrates the sealing function where needed while leaving other areas free from contact, reducing overall friction and thermal expansion effects.

Inventive Principle:
Principle #3Local quality

2Reliability

If additional sealing components such as brush or honeycomb seals are added, then sealing effectiveness is improved, but manufacturing cost and device complexity increase

Engineering Contradiction:
Improvesealing effectivenessVSAvoidadditional components requiring assembly, welding or brazing
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing ribs are merged directly into the stator vane structure as an integral feature rather than being separate components. This integration eliminates the need for additional sealing components, assembly operations, welding, or brazing, thereby reducing device complexity and manufacturing cost while maintaining sealing effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sealing ribs are designed to be self-contained features of the stator vane that perform the sealing function without requiring external components or complex assembly processes. The sealing structure is self-sufficient, eliminating dependency on additional parts and simplifying manufacturing.

Inventive Principle:
Principle #25Self-service

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

The design minimizes contact area between stator and rotor components, reducing friction and damage while maintaining effective sealing, and is cost-effective by integrating the sealing ribs within the existing structure, allowing for flexible adaptation to thermal expansion without compromising sealing performance.

Implementation Method 1

in use the stator aft sealing portion contacts a respective adjacent rotor portion of a gas turbine rotor in response to thermal expansion only at the at least one aft sealing rib

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3926141B1Gas turbine stator vane with sealing member and method for modifying a gas turbine stator vane
Publication Date: 2024.03.13 ANSALDO ENERGIA SPA
  • EP3926141B1 patent drawingFigure 1~2
  • EP3926141B1 patent drawingFigure 3~5
  • EP3926141B1 patent drawingFigure 6~7

AI summary

A gas turbine stator vane includes, an airfoil (13), having a leading edge (13a) and a trailing edge (13b), an outer platform (14), connected to an outer end of the airfoil (13), and an inner platform (15), connected to an inner end of the airfoil (13). The inner platform (15) has a front edge (15a) and an aft edge (15b) at the leading edge (13a) and at the trailing edge (13b) of the airfoil (13), respectively and includes a stator aft sealing portion (19) at the aft edge (15b) and at least one aft sealing rib (20), integral with the inner platform (15) and delimited by adjacent aft grooves (21) that extend parallel to each other all along the aft edge (15b) in the stator aft sealing portion (19), whereby in use the stator aft sealing portion (19) contacts a respective adjacent rotor portion of a gas turbine rotor (3) in response to thermal expansion only at the at least one aft sealing rib (20).