Turbine Shroud Segmented Design Thermal Expansion

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Solution Overview

Problem

Turbine shrouds in gas turbine engines face challenges due to components with different coefficients of thermal expansion, leading to attachment issues and potential gas leakage, as they expand at different rates under high combustion temperatures.

Innovation Solution

A segmented turbine shroud design incorporating a carrier segment, blade track segments, and a mounting system with tandem seals and braces that include wire and rope seals, which accommodate thermal expansion differences and maintain a gas-tight seal through a unique groove configuration and hanger arrangement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If components with different coefficients of thermal expansion are used in the turbine shroud, then the shroud can withstand high combustion temperatures, but the components expand at different rates causing attachment issues and potential gas leakage

Engineering Contradiction:

Improvecombustion temperature resistanceVSAvoidattachment reliability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The turbine shroud is divided into multiple segments including a carrier segment and blade track segments that can independently expand and contract. This segmentation allows each component to accommodate its thermal expansion without compromising the overall structural integrity or attachment reliability under high temperature conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A seal member comprising a wire seal and a rope seal is employed to create a flexible sealing arrangement between components with different thermal expansion rates. The wire seal provides structural support while the rope seal provides the flexible sealing function, allowing the seal to accommodate differential expansion without failing.

Inventive Principle:

Principle #30Flexible shells and thin films

2Reliability

If rigid sealing methods are used between components, then gas-tight seal can be maintained, but the sealing fails under thermal expansion differences

Engineering Contradiction:

Improveseal integrityVSAvoidthermal expansion accommodation

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The seal member uses a rope seal made of flexible material that can deform and conform to the varying gaps between components during thermal expansion and contraction. This flexible sealing approach maintains gas-tight integrity while adapting to dimensional changes in the turbine shroud components.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The sealing system is designed to accommodate changes in physical parameters (dimensions, gaps) caused by thermal expansion. The wire seal and rope seal configuration allows the sealing parameters to dynamically adjust as the temperature and dimensional parameters of the components change during operation.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If a segmented turbine shroud design is used, then thermal expansion differences can be accommodated, but the assembly complexity increases

Engineering Contradiction:

Improvethermal expansion accommodationVSAvoidassembly complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The turbine shroud is segmented into a carrier segment and blade track segments that are designed to be relatively simple in individual structure but work together to solve the thermal expansion problem. Each segment is independently manufacturable and can be assembled using standardized connection methods.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The seal member acts as an intermediary element between the carrier segment and blade track segments, simplifying the connection by providing both sealing and positioning functions in a single component arrangement, thereby reducing the overall assembly complexity despite the segmented design.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution effectively seals radial gaps between components with different thermal expansion rates, ensuring reliable operation and maintaining a gas-tight seal, even under varying temperature conditions, thereby enhancing the structural integrity and efficiency of the turbine shroud.

Implementation Method 1

The mounting system is configured to couple the blade track segment to the carrier segment such that the blade track segment is radially movable relative to the carrier segment. Tandem seals are arranged radially between the carrier segment and the blade track segments to block the flow of gasses.

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3330492B1Turbine shroud assembly with Anti-rotation features

Publication Date: 2020.10.28 ROLLS ROYCE CORP

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AI summary

An assembly adapted for use in a gas turbine engine (10) has a carrier component (24) and a supported component (26). The assembly including a mounting system (28) for coupling the supported component (26) to the carrier component (24) and a seal (30) adapted to resist the movement of gasses between the supported component (26) to the carrier component (24). In an illustrative embodiment, the assembly is a turbine shroud segment (20) for blocking gasses from passing over turbine blades (13) included in the gas turbine engine (10).