Sacrificial Mount Layers for CMC Turbine Vane Re-Staggering

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Solution Overview

Problem

Re-staggering ceramic matrix composite (CMC) static vanes in gas turbine engines is challenging due to the difficulty in machining the mount structures without compromising their structural integrity.

Innovation Solution

A sacrificial coating or plies are applied to the mount structures of CMC vanes, allowing for precise re-staggering by machining away the sacrificial material to align the vanes, ensuring structural integrity is maintained.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If re-staggering is performed on CMC static vanes by machining the mount structure, then alignment precision is improved, but structural integrity deteriorates

Engineering Contradiction:

Improvealignment precisionVSAvoidstructural integrity

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The mount structure is segmented into two functional parts: a sacrificial coating layer ( removable layer) and the underlying CMC substrate. The sacrificial layer is specifically designed to be machined away to achieve re-stagger alignment, while the CMC substrate maintains its structural integrity and is protected from machining operations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A sacrificial coating or plies are applied as an intermediary layer between the machining tool and the CMC mount structure. This intermediary layer absorbs the machining action, allowing precise re-stagger to be achieved without directly compromising the structural CMC material.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If re-staggering is performed to adjust flow area, then turbine stage performance is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveturbine stage performanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The sacrificial coating is applied to the mount structure before the re-stagger machining operation. This preliminary action prepares the surface for machining by providing a material that can be removed to achieve the desired alignment, simplifying the overall manufacturing process compared to attempting to machine the CMC directly.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sacrificial coating is designed as a disposable, consumable layer that is intentionally removed during the re-stagger process. This temporary material enables the performance adjustment while keeping the permanent structural components (CMC vanes) intact and reusable.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP4379190B1Removable layer to adjust mount structure of a turbine vane for re-stagger

Publication Date: 2025.10.01 RTX CORP

Figure 1
Figure 2A~2C
Figure 3A~3C

AI summary

A plurality of static stator vanes (106A,106B) are circumferentially spaced in a row axially intermediate rows of turbine blades. Each stator vane (106A,106B) has at least an outer platform with mount structure. Each of the stator vanes (106A,106B) are formed of composite materials. The mount structure is provided with sacrificial material. At least a first of the stator vanes (106B) is circumferentially adjacent to a second of the stator vanes (106A). An orientation of the first of the stator vanes (106B) is re-staggered relative to the second of the stator vanes (106A). The sacrificial material of the first of the stator vanes (106B) is machined away such that a final trailing edge (122B) of the first of the stator vanes mount structure is now better axially aligned with the trailing edge (122B) of the second of the stator vanes mount structure.