Gas Turbine Blade Squealer Tip Cooling for Lower Thermal Load

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Solution Overview

Problem

Gas turbine engine blades face challenges in efficiently managing high thermal loads due to exposure to hot combustion or exhaust gases, leading to potential material softening or melting, and existing cooling methods often result in aerodynamic inefficiencies and increased cooling fluid usage.

Innovation Solution

The design incorporates a squealer tip with an internal squealer tip cooling channel, formed by brazing a presintered preform with abrasive ceramic particles, which includes a first and second squealer tip rail and a squealer tip cap, connected to an internal cooling circuit to reduce thermal loading and improve aerodynamics by internal cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If external cooling methods are used to cool the blade tip, then cooling effectiveness is achieved, but aerodynamic efficiency deteriorates and cooling fluid usage increases

Engineering Contradiction:
Improveblade tip temperatureVSAvoidaerodynamic efficiency
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The cooling channel is nested within the squealer tip structure itself. The blade tip defines a supply aperture that fluidly connects the internal cooling circuit and the internal squealer tip cooling channel, creating a nested configuration where the cooling function is integrated within the structural component rather than being external.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The cooling function is merged with the squealer tip structure by forming the internal squealer tip cooling channel using the squealer tip cap, first squealer tip rail, second squealer tip rail, and blade tip as integrated components. This combines the structural and cooling functions into a single unified element.

Inventive Principle:
Principle #5Merging (Combining)

2Temperature

If cooling fluid is used to cool the blade tip, then thermal loading is reduced, but cooling fluid usage increases

Engineering Contradiction:
Improvethermal loading on blade tipVSAvoidcooling fluid usage
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

The squealer tip structure serves itself by containing the cooling channel within its own geometry. The blade tip, squealer tip cap, and rails together form both the structural element and the cooling passage, allowing the component to provide its own cooling without requiring separate external cooling systems.

Inventive Principle:
Principle #25Self-service

3Productivity

If the blade tip is exposed to hot combustion gases, then aerodynamic performance is maintained, but material softening or melting occurs

Engineering Contradiction:
Improveaerodynamic performanceVSAvoidmaterial integrity
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The internal squealer tip cooling channel provides localized cooling precisely where the blade tip is exposed to hot combustion gases. The cooling is applied locally to the critical thermal zone without requiring changes to the overall blade aerodynamic shape, maintaining aerodynamic performance while protecting material integrity in the specific high-temperature region.

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 solution effectively reduces thermal loading on the squealer tip, minimizes cooling fluid usage, and enhances aerodynamic efficiency by internalizing the cooling process, thereby improving the overall performance of the gas turbine engine.

Implementation Method 1

passing of a cooling fluid, such as cooling air, across or through a portion of the component

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

cooling of such components including, for example, application of a thermal barrier coating to the component

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

brazing a presintered preform defining a first squealer tip rail, a second squealer tip rail adjacent to the first squealer tip rail, and a squealer tip cap extending between the first and second squealer tip rails

Methodology Applied
Scientific EffectBrazing: Brazing

Data Source

PatentEP3575555B1Gas turbine engine blade and method of forming a gas turbine engine blade
Publication Date: 2023.10.25 ROLLS ROYCE CORP
  • EP3575555B1 patent drawingFigure 1A~1B
  • EP3575555B1 patent drawingFigure 2
  • EP3575555B1 patent drawingFigure 3~4

AI summary

A gas turbine engine blade (10) may include an airfoil (16, 40, 60) extending radially from a base to a blade tip (28, 41, 72, 114, 134), the airfoil including a pressure sidewall (17, 47, 68) and a suction sidewall (19, 49, 66) each extending between a leading edge (18, 48) and a trailing edge (20, 50) opposite the leading edge, an internal cooling circuit (22, 70) extending from the base to the blade tip; and a squealer tip (24, 42, 62). The squealer tip may include a first squealer tip rail (25, 45, 74, 116, 136) and a second squealer tip rail (26, 46, 76, 118, 138) adjacent to the first squealer tip rail, and a squealer tip cap (27, 78, 120, 140) extending between the first and second squealer tip rails. The blade tip, the first and second squealer tip rails, and the squealer tip cap may define an internal squealer tip cooling channel (44, 64, 110, 130). The blade tip may define a supply aperture (52, 86) that fluidly connect the internal cooling circuit and the internal squealer tip cooling channel.