Turbine Exhaust Case Strut Cooling via Compressed Air Manifold

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Solution Overview

Problem

Gas turbine engine turbine exhaust casing (TEC) materials face high operating temperatures, leading to increased manufacturing and maintenance costs due to the need for expensive, high-temperature-resistant materials like Inconel 718 or Haynes 282, especially during prolonged taxi times and high ambient conditions.

Innovation Solution

A cooling arrangement where compressed air from the compressor is selectively communicated into hollow struts of the TEC through a manifold with radially extending channels and holes, providing targeted cooling to the leading and trailing edges of the struts, allowing for the use of lower-grade materials and reducing weight and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If expensive high-temperature-resistant materials like Inconel 718 or Haynes 282 are used to manufacture the TEC, then the TEC can withstand very high operating temperatures (750-800°C), but the manufacturing cost and material cost increase significantly

Engineering Contradiction:
Improveoperating temperature resistanceVSAvoidmanufacturing cost
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

A cooling air manifold system acts as an intermediary between the compressor and TEC struts, delivering compressed cooling air through radially extending channels to selectively cool the struts. This mediator system enables the use of lower-cost materials by actively managing heat transfer between the exhaust gases and strut surfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention uses pneumatic cooling by directing compressed air from the compressor through a manifold system and into the TEC struts. The pressurized air flow through channels and holes provides active cooling, replacing the need for expensive heat-resistant materials with a cost-effective fluid-based thermal management solution.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Reliability

If expensive high-temperature-resistant materials are selected for the TEC, then the TEC can operate safely at high temperatures during prolonged taxi times, but the maintenance cost increases

Engineering Contradiction:
Improvesafe operation at high temperatureVSAvoidmaintenance cost
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The cooling air manifold serves as an intermediary system that actively manages thermal conditions in the TEC struts during high-temperature operation. By controlling the delivery of compressed cooling air, the system maintains strut temperatures within safe operating limits, reducing thermal stress and extending component life without requiring expensive material upgrades.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the thermal parameters of the TEC struts by introducing compressed cooling air that lowers the operating temperature of the struts during high-heat conditions. This parameter change (temperature reduction) allows the use of standard materials while maintaining reliability, thereby reducing maintenance costs associated with high-temperature material degradation.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If a cooling system is added to the TEC struts, then the operational temperature range is extended and lower-grade materials can be used, but the device complexity increases

Engineering Contradiction:
Improveoperational temperature rangeVSAvoidcooling system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cooling air manifold system performs multiple functions: it distributes compressed cooling air to multiple TEC struts simultaneously, integrates with the existing compressor air supply, and provides selective cooling to different strut locations. This multi-functionality reduces overall system complexity by consolidating cooling delivery into a single integrated manifold structure rather than requiring separate cooling systems for each strut.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cooling system is segmented into modular components: a central manifold with radially extending channels, individual channel-outlet assemblies for each strut, and integrated holes in the strut surfaces. This segmentation allows for easier manufacturing, assembly, and maintenance while achieving comprehensive cooling coverage across multiple struts through a systematic distributed architecture.

Inventive Principle:
Principle #1Segmentation

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 extends the operational temperature range of the engine, enables the use of less expensive materials, and reduces manufacturing and maintenance costs by effectively cooling the TEC struts, while minimizing additional weight and complexity.

Implementation Method 1

compressed air from said at least one compressor is communicated into said at least one hollow strut to cool said TEC

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

an air duct arranged to communicate compressed air from said at least one compressor into at least one of said hollow struts

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Data Source

PatentEP3682091B1Turbine exhaust case cooling
Publication Date: 2022.04.06 GKN AEROSPACE SWEDEN AB
  • EP3682091B1 patent drawingFigure 1~2
  • EP3682091B1 patent drawingFigure 3~4
  • EP3682091B1 patent drawingFigure 5~6

AI summary

The invention concerns a turbine exhaust casing (TEC) cooling arrangement for a gas turbine engine. The arrangement involves cooling the struts of a TEC using compressed air communicated from one of the engine's compressors.