Gas Turbine Heat Shield Radial Tabs Axial Retention

Solution Overview

Problem

Significant temperature differences between rotor cavities in gas turbine engines complicate the initial radial interference fit requirements for assembly and disassembly, especially when components are mated by a radial interference fit.

Innovation Solution

A heat shield with radial tabs and a circumferentially intermittent slot structure is used to provide axial retention and reduce the initial radial interference fit between the high pressure turbine and compressor, allowing for easier assembly and disassembly by acting as a thermal insulator and bayonet lock.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a radial interference fit is used to mate components forming adjacent rotor cavities, then the initial radial interference fit requirements for assembly and disassembly are complicated, but the axial retention and thermal insulation between high pressure turbine and compressor are improved

Engineering Contradiction:

Improveaxial retentionVSAvoidassembly and disassembly

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The heat shield is segmented into multiple radial tabs that can be independently positioned within circumferentially intermittent slots. This segmentation allows the heat shield to provide axial retention through the bayonet lock mechanism while enabling easier assembly and disassembly by permitting rotational movement during installation and maintenance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The heat shield acts as an intermediary component between the high pressure turbine and compressor, providing thermal insulation to reduce temperature differences while the radial tabs and slots mechanism serves as an intermediary locking system that provides axial retention without complicating assembly and disassembly operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Temperature

If a heat shield is added to provide thermal insulation between high pressure turbine and compressor, then temperature differences are reduced, but device complexity increases

Engineering Contradiction:

Improvetemperature differenceVSAvoidstructure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The heat shield is designed to perform multiple functions simultaneously: it provides thermal insulation between the high pressure turbine and compressor, provides axial retention through the bayonet lock mechanism with radial tabs and slots, and allows for easier assembly and disassembly. This multi-functionality reduces the need for separate components and justifies the structural complexity by delivering multiple benefits from a single integrated solution.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 heat shield facilitates a smaller initial radial interference fit, simplifying the assembly and disassembly process while maintaining axial engagement and thermal insulation between the high pressure turbine and compressor.

Implementation Method 1

A heat shield with radial tabs and a circumferentially intermittent slot structure is used to provide axial retention and reduce the initial radial interference fit between the high pressure turbine and compressor, allowing for easier assembly and disassembly by acting as a thermal insulator and bayonet lock.

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

A heat shield with radial tabs and a circumferentially intermittent slot structure is used to provide axial retention and reduce the initial radial interference fit between the high pressure turbine and compressor, allowing for easier assembly and disassembly by acting as a thermal insulator and bayonet lock.

Methodology Applied

Scientific EffectMechanical fastening: Mechanical Fastener

Implementation Method 3

The rotation may permit a reduction in the initial radial interference fit at contact points between a high pressure turbine and a high pressure compressor.

Methodology Applied

Scientific EffectRotational movement:

Data Source

PatentEP2474707B1Multi-function heat shield for a gas turbine engine

Publication Date: 2018.10.31 UNITED TECH CORP

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AI summary

A rotor disk assembly for a gas turbine engine includes a rotor disk (56) with a circumferentially intermittent slot structure (94) that extends radially outward relative to an axis of rotation. A heat shield (52) has a multiple of radial tabs (88) engageable with the circumferentially intermittent slot structure (94) to provide axial retention of a cover plate (54) to the rotor disk (56).