Heat Shield Cooling Strut in Gas Turbine Engine

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Solution Overview

Problem

In gas turbine engines, the fairing is exposed to high temperatures due to direct gas flow, causing it to heat up and subsequently heat the frame undesirably, leading to inefficiencies and material costs.

Innovation Solution

A heat shield is positioned around the strut and between the strut and the fairing, directing a cooler secondary air flow along the strut to enhance cooling and is attached to the frame rather than the fairing, avoiding conduction heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the fairing is directly exposed to gas flow including combustion gases, then the fairing can be heated to high temperatures during operation, but heat from the fairing heats the frame in an undesirable manner

Engineering Contradiction:
Improvefairing temperatureVSAvoidheat transfer to frame
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

A heat shield is introduced as an intermediary component between the fairing and the frame. The heat shield is positioned to block radiant heat transfer from the hot fairing to the frame, and it is cooled by secondary air flow to further reduce heat conduction to the frame, thus protecting the frame from thermal damage

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the heat shield is attached to the fairing, then it can block heat transfer, but conduction heating occurs from the fairing to the heat shield

Engineering Contradiction:
Improveheat transfer to frameVSAvoidheat shield temperature
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

Secondary air flow is directed through passages in the heat shield and along its surface, creating a cooling effect that reduces the temperature of the heat shield. This pneumatic cooling system prevents excessive heat buildup in the heat shield, allowing it to effectively block heat transfer from the fairing to the frame without suffering from conduction heating itself

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Reliability

If expensive heat-resistant materials are used in the fairing, then the fairing can withstand high temperatures, but the cost of construction increases

Engineering Contradiction:
Improvefairing heat resistanceVSAvoidconstruction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The heat shield acts as a thermal barrier that protects the frame from heat generated by the fairing. This allows the fairing to be constructed from less expensive materials that do not require the same level of heat resistance, while the heat shield (which is actively cooled) handles the thermal protection function

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

This configuration increases the efficiency of the gas turbine engine and allows for the use of less expensive materials in the fairing construction by effectively managing heat and reducing conduction heating.

Implementation Method 1

directing a cooler secondary air flow along the strut to maximize effectiveness of the cooler air in cooling the strut

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

Heat from the fairing can heat the frame in an undesirable manner

Methodology Applied
Scientific EffectThermal Radiation: Thermal Radiation

Implementation Method 3

This configuration avoids attachment of the heat shield to the fairing, which is undesirable due to conduction heating from the fairing to the heat shield

Methodology Applied
Scientific EffectThermal Conduction: Conduction (thermal)

Data Source

PatentEP2938857B2Heat shield for cooling a strut
Publication Date: 2020.11.25 UNITED TECH CORP
  • EP2938857B2 patent drawingFigure 1
  • EP2938857B2 patent drawingFigure 2
  • EP2938857B2 patent drawingFigure 3

AI summary

An assembly for a gas turbine engine includes a strut and a heat shield. The heat shield is disposed adjacent the strut and the heat shield and is adapted to contain a cooling air flow that passes along first cavity between the heat shield and the strut.