Sealing Vane Segments via Pressurized Cavity

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Solution Overview

Problem

Gas turbine engines face cooling air leakage and hot gas ingestion due to inadequately sealed circumferential gaps between segmented vane rings, which compromises efficiency and performance.

Innovation Solution

The implementation of a segmented vane array with annular seal housings and insulation tubes to create pressurized cavities that utilize cooling air to maintain a pressure differential, preventing leakage through gaps between duct wall segments, and featuring an air sealing system with annular seal housings and insulation tubes to isolate the axial gaps from the hot gas path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If feather seals are used to seal circumferential gaps between segmented vane rings, then the structure is simple and easy to manufacture, but cooling air leakage into the hot gas path and hot gas ingestion still occur due to inadequate sealing

Engineering Contradiction:

Improvesealing effectivenessVSAvoidseal structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A pressurized cavity filled with cooling air is introduced as an intermediary between the hot gas path and the circumferential gaps. This pressurized cooling air cavity acts as a mediator that prevents hot gas from leaking through the gaps by maintaining a pressure differential, thereby improving sealing effectiveness without requiring complex seal structures

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention utilizes pneumatic pressure by introducing pressurized cooling air into the cavity formed by the seal housing. This pressurized air creates a pressure differential across the circumferential gaps, using gas pressure to prevent hot gas ingestion and cooling air leakage, thus resolving the sealing effectiveness issue

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Loss of energy

If circumferential gaps between segments are sealed, then cooling air leakage and hot gas ingestion are reduced, but the device complexity increases due to additional seal housings and insulation tubes

Engineering Contradiction:

Improvecooling air leakageVSAvoidseal housing and insulation tube structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The seal housing and insulation tubes are merged into an integrated assembly that combines sealing functionality with thermal insulation. This unified structure reduces the number of separate components and simplifies installation while effectively preventing both cooling air leakage and hot gas ingestion through the circumferential gaps

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The seal housing structure serves multiple functions simultaneously: it contains the pressurized cooling air cavity, provides thermal insulation through integrated insulation tubes, and seals the circumferential gaps. This multi-functionality reduces the need for separate components, thereby reducing overall device complexity while addressing energy loss

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If pressurized cooling air is used to create a pressure differential, then sealing effectiveness is improved, but the use of energy increases due to continuous pressurization requirements

Engineering Contradiction:

Improvesealing performanceVSAvoidcooling air pressurization energy

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The pressurized cooling air cavity serves a dual purpose: it maintains sealing performance by creating a pressure differential across the gaps, and simultaneously provides thermal cooling to the duct walls. This self-service approach means the pressurized cooling air performs both sealing and cooling functions, reducing the need for separate systems and optimizing energy utilization

Inventive Principle:

Principle #25Self-service

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 cooling air leakage and hot gas ingestion, enhancing the sealing efficiency and maintaining a pressurized environment within the engine, thereby improving the overall performance and efficiency of the gas turbine engine.

Implementation Method 1

the seal housing sealingly mounted within the engine to in use permit said cooling air to provide a pressure differential in the case cavity relative to the duct cavity

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

a plurality of insulation tubes aligning with the openings in the respective first and second seal housings, to surround the respective load spokes and to be attached to the first and second seal housings

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS8500392B2Sealing for vane segments

Publication Date: 2013.08.06 PRATT & WHITNEY CANADA CORP

AI summary

A seal housing is provided to substantially cover at least one duct wall of vane array duct of a gas turbine engine, and one example arrangement is employed in a mid-turbine frame. The arrangement provides improved sealing of the vane array duct through the provision of a plurality of cavities extending along the duct wall. The arrangement may also include insulation tubes to assist in sealing around load transfer spokes passing through the vane array.