Gas Turbine Blade Tip Grinding with Porous Ceramic Coating

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Solution Overview

Problem

Existing blade arrangements in gas turbines face challenges in minimizing the gap between rotating rotor blades and stationary heat shields due to complex structures and increased manufacturing efforts, particularly in achieving efficient grinding without special abrasive layers.

Innovation Solution

A blade arrangement featuring a porous ceramic thermal insulation layer on the heat shield and a homogeneous MCrAlY covering layer on the blade tip, allowing the blade tip to grind into the heat shield without a special abrasive layer, thereby optimizing the gap and simplifying production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a special grinding layer with abrasive bodies is applied to the blade tip, then the gap between blade tip and heat shield is minimized, but the manufacturing complexity and cost increase

Engineering Contradiction:

Improvegap widthVSAvoidblade tip structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts the abrasive function from a complex embedded grinding layer and concentrates it into a simple protruding grinding element on the blade tip. This eliminates the need for carrier layers and embedded abrasive bodies while maintaining the gap-minimizing grinding function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The grinding element is designed as a simple, replaceable protruding feature on the blade tip that can be easily worn and re-sharpened or replaced, rather than being part of a complex permanent grinding layer structure.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If a complex multilayer preform with abrasive coating is used on the blade tip, then grinding performance is improved, but the manufacturing effort and cost increase

Engineering Contradiction:

Improvegrinding capabilityVSAvoidmanufacturing effort

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention extracts the essential grinding function from complex multilayer preforms with embedded abrasives and implements it through a simple protruding grinding element, dramatically reducing manufacturing complexity while maintaining grinding effectiveness.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of applying a complex abrasive coating to the blade tip, the invention inverts the approach by having the blade tip itself feature a simple protruding grinding element that performs the abrasion function without requiring additional coating layers.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If the clearance between blade tip and heat shield is increased to prevent grinding, then component damage is avoided, but gas turbine efficiency decreases

Engineering Contradiction:

Improvecomponent durabilityVSAvoidgas turbine efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The invention applies preliminary action by providing a controlled grinding element on the blade tip that proactively wears into the heat shield coating during operation, creating a precise fit before damage can occur. This allows the clearance to remain small while preventing component damage through controlled wear.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the physical state of the blade tip by adding a protruding grinding element that alters the contact mechanics, enabling controlled abrasion against the heat shield coating to create a precise fit, thereby changing the clearance parameter from a fixed gap to a dynamically adjusted fit.

Inventive Principle:

Principle #35Parameter changes

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 solution effectively minimizes the gap between the blade tip and heat shield, enhancing the efficiency of the gas turbine by allowing grinding without additional abrasive media, thus reducing manufacturing complexity and maintaining thermal insulation properties.

Implementation Method 1

the blade tip to wear into the heat shield

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

porous thermal insulation layer made of a porous ceramic layer

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP2313615B2Blade arrangement of a gas turbine

Publication Date: 2023.09.27 ANSALDO ENERGIA IP UK LTD

Figure 1~2
Figure 3

AI summary

The invention relates to the blade arrangement (30) of a gas turbine with at least one blade (11), which protrudes in the radial direction into a hot gas channel (13) arranged concentrically in relation to an axis (16) and ends in a blade tip (27), which lies opposite, with a clearance (25), a heat shield (12) bounding the hot gas channel (13), wherein the blade (11) and the heat shield (12) are movable in relation to each other in the circumferential direction, and the blade tip (27) and the heat shield (12) are covered with layers (22, 23, 24) that make it possible for the blade tip (27) to grind into the heat shield (12) in a specifically intended manner. With such a blade arrangement, a reduction in the clearance by allowing grinding-in is achieved in a simplified way by the heat shield (12) having an exterior abradable layer of a porous thermal barrier coating (23), and by the blade tip (27) being provided with a homogeneous metallic covering layer (24).