Ceramic Composite Heat Shield for High-Temperature Aircraft Engines

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Solution Overview

Problem

Existing aircraft heat shields made of titanium have a limited temperature capacity, requiring higher idle thrust and increased fuel consumption and brake wear due to inefficient engine operation.

Innovation Solution

A ceramic composite heat shield with a concave lower surface and convex upper surface, featuring thickened panel edge portions and side skins, providing a high-temperature capacity and minimal thermal expansion for efficient thermal isolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If titanium heat shield is used, then structural strength and thermal isolation are provided, but temperature capacity is limited to about 1100 degrees F

Engineering Contradiction:

Improvetemperature capacityVSAvoidmaterial reliability at high temperature

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent applies composite materials by using ceramic matrix composite (CMC) material for the heat shield panel. This composite material combines ceramic fibers embedded in a ceramic matrix, providing both high temperature capacity (exceeding 1100 degrees F) and structural reliability. The composite structure enables the heat shield to withstand temperatures beyond titanium's limit while maintaining structural integrity through the fiber-reinforced ceramic matrix.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If titanium heat shield is used, then thermal isolation is achieved, but engine must operate at higher idle thrust to maintain efficient temperature

Engineering Contradiction:

Improvefuel consumptionVSAvoididle exhaust temperature

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The patent applies parameter changes by transitioning from titanium material to ceramic matrix composite material, which fundamentally changes the temperature parameter range in which the heat shield can operate. This material parameter change enables the engine to operate at higher idle exhaust temperatures without exceeding heat shield limits, thereby improving fuel efficiency and reducing the need for higher idle thrust.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If titanium heat shield is used, then structural integrity is maintained, but thermal expansion requires multiple segmented sections

Engineering Contradiction:

Improveheat shield structureVSAvoidthermal expansion stability

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The patent applies thermal expansion principles by selecting ceramic matrix composite material that has thermal expansion characteristics compatible with adjacent titanium structures. The CMC material's thermal expansion properties allow for a one-piece heat shield construction that can thermally cycle with titanium components without requiring segmented sections, thereby simplifying the overall structure while maintaining thermal expansion stability.

Inventive Principle:

Principle #37Thermal expansion

4Duration of action of stationary object

If higher idle thrust is used to maintain titanium heat shield temperature limits, then temperature capacity is preserved, but brake wear increases

Engineering Contradiction:

Improvebrake service lifeVSAvoidfuel consumption

Core Design Contradiction:

Duration of action of stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent applies composite materials to enable the engine to operate at optimal temperatures without excessive idle thrust. By using CMC heat shield material with higher temperature capacity, the system avoids the need for higher thrust operation that would increase brake wear, thereby extending brake service life while maintaining efficient fuel consumption through normal operating conditions.

Inventive Principle:

Principle #40Composite materials

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

Enables operation of aircraft engines at lower idle thrust and higher temperatures, reducing fuel consumption and brake wear while maintaining structural integrity and thermal isolation.

Implementation Method 1

a ceramic composite heat shield panel having a generally concave first surface and a generally convex second surface... providing a high-temperature capacity and minimal thermal expansion for efficient thermal isolation

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

The ceramic heat shield may undergo minimal thermal expansion during aircraft engine thermal cycling

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS7943227B2Ceramic heat shield

Publication Date: 2011.05.17 THE BOEING CO

AI summary

A heat shield includes a ceramic composite heat shield panel having a generally concave first surface and a generally convex second surface and a pair of thickened panel edge portions provided in the heat shield panel. A heat shield assembly is also disclosed.