Variable Flowpath Casing for Turbine Blade Tip Clearance Control

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Solution Overview

Problem

Turbine engines face challenges in maintaining optimal tip clearance between rotor blades and casings due to differential thermal expansion of materials, leading to performance losses and potential blade tip rubbing.

Innovation Solution

The implementation of a variable flowpath casing with a flexible inner substrate and a tension component, allowing for adjustable tip clearance control by adjusting the casing flowpath surface during operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a fixed casing is used, then the structure is simple and easy to manufacture, but the tip clearance cannot be adjusted leading to performance losses and blade tip rubbing

Engineering Contradiction:

Improvetip clearance controlVSAvoidcasing structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by transforming the fixed casing into a variable geometry casing that can adjust its flowpath dimensions. The casing includes movable components such as adjustable stators or variable geometry elements that allow the flowpath cross-sectional area to change dynamically, enabling tip clearance control during operation while maintaining structural integrity

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The casing is divided into multiple adjustable segments or sections rather than being a single rigid structure. This segmentation allows independent adjustment of different portions of the flowpath to control tip clearance at specific locations, resolving the contradiction between operational flexibility and structural simplicity

Inventive Principle:

Principle #1Segmentation

2Reliability

If the casing flowpath is made variable to control tip clearance, then performance losses are reduced and blade tip rubbing is prevented, but the manufacturing complexity increases

Engineering Contradiction:

Improveblade tip clearance maintenanceVSAvoidcasing fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs flexible shell structures or thin film components within the casing that can deform or adjust position to control tip clearance. These flexible elements are designed to be manufacturable using standard techniques while providing the necessary variability in the flowpath geometry

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The invention utilizes parameter changes in the casing geometry, such as variable thickness, adjustable curvature, or modifiable cross-sectional dimensions, to control tip clearance. These parameter variations are incorporated into the manufacturing process through programmable methods or adjustable mechanisms that maintain ease of fabrication

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250290427A1Variable flowpath casings for blade tip clearance control

Publication Date: 2025.09.18 GENERAL ELECTRIC CO

AI summary

Disclosed herein are example variable flowpath casings for blade tip clearance control. An example casing for a turbine engine includes a first annular substrate extending along an axial direction, the first annular substrate defining a cavity at a radially inward surface of the first annular substrate, a second annular substrate positioned at least partially within the cavity of the first annular substrate, and a tension belt extending circumferentially around a periphery of the second annular substrate.