Microporous Insulation for Rocket Nozzle Thermal Management

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Solution Overview

Problem

The challenge is to provide effective thermal insulation for the thrust nozzle of rocket and ram engines, ensuring the metallic outer structure does not overheat during cruise flight, while minimizing installation space and preventing damage from vibrations, given the constraints of limited space and extreme temperatures.

Innovation Solution

A passive high-temperature thermal insulation system using a metallic outer casing with a profiled, mirrored metal foil and microporous insulating material, combined with a protective fabric and film, to reduce heat transfer and mechanical stress, ensuring uniform insulation and structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a thin metallic outer casing is used to minimize installation space, then the volume between the thrust nozzle and outer structure is reduced, but the thermal insulation effectiveness deteriorates due to reduced space for insulation material

Engineering Contradiction:
Improveinstallation spaceVSAvoidthermal insulation effectiveness
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent employs microporous insulating material with a porosity of 80-95% to achieve superior thermal insulation performance within the constrained space. The microporous structure provides extremely low thermal conductivity, allowing effective insulation with minimal material thickness, thus resolving the contradiction between limited installation volume and thermal insulation effectiveness.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent uses a composite structure combining a metallic outer casing (steel or nickel-based alloy) with microporous insulating material. This composite design allows the thin metallic casing to provide structural integrity while the microporous material provides thermal insulation, achieving both space minimization and thermal protection.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If passive high-temperature insulation is used without a metallic outer casing, then the assembly process becomes more complex and positioning is difficult, but the thermal insulation performance is reduced

Engineering Contradiction:
Improveassembly simplicityVSAvoidthermal insulation performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a thin metallic outer casing (0.05-0.5 mm thickness) that can be formed into a cylindrical shape to enclose the microporous insulating material. This flexible thin-film approach simplifies assembly compared to rigid structures while maintaining thermal insulation performance through the enclosed microporous material.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent implements a nested structure where the microporous insulating material is placed inside the metallic outer casing, creating a layered configuration. This nesting approach simplifies assembly by containing the insulation material within a protective shell, ensuring proper positioning and maintaining thermal performance.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Weight of moving object

If the metallic outer casing is made thinner to reduce mass, then the mass between thrust nozzle and outer structure is reduced, but the casing becomes more susceptible to damage from vibration and chafing

Engineering Contradiction:
Improvemass of outer casingVSAvoidresistance to vibration and chafing
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent creates a composite system where a thin metallic outer casing (reducing mass) protects the microporous insulating material. The metallic casing acts as a protective shell that resists vibration and chafing damage, while the thin design minimizes added mass, resolving the contradiction between weight reduction and strength requirements.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs a thin-film metallic casing (0.05-0.5 mm) that provides mechanical protection against vibration and chafing while maintaining minimal mass. The thin-film structure is sufficient to protect the insulation material without adding excessive weight, balancing mass reduction with durability requirements.

Inventive Principle:
Principle #30Flexible shells and thin films

4Device complexity

If the microporous insulating material is placed directly without a metallic outer casing, then the thermal insulation is exposed to direct mechanical stress, but the assembly process becomes more complex

Engineering Contradiction:
Improveassembly complexityVSAvoidmechanical protection of insulation material
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The patent nests the microporous insulating material within the metallic outer casing, creating a protective enclosure. This nested configuration protects the insulation material from mechanical stress while simplifying assembly, as the casing provides a ready-made container for the insulation material.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent uses a flexible thin-film metallic casing to enclose the microporous insulating material. This thin-film shell provides mechanical protection against vibration and chafing while maintaining assembly simplicity through its formable and adaptable nature.

Inventive Principle:
Principle #30Flexible shells and thin films

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 prevents overheating of the metallic outer structure, maintaining the functionality of electromechanical components and structural integrity during cruise flight, even at temperatures exceeding 2,500°C, by utilizing a modular design with a thin metallic casing and microporous insulation, which is flexible and resistant to thermal damage.

Implementation Method 1

the thermal insulation must be optimized in such a way that, using the smallest possible volume, it reduces the heating of the outer structure

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

the metallic outer casing has the smallest possible layer thickness. The metallic outer casing is preferably formed by a metal foil

Methodology Applied
Scientific EffectThermal radiation reflection: Reflection

Data Source

PatentEP2048344B1Jet or rocket engine with heat insulated exhaust nozzle
Publication Date: 2015.01.14 BAYERN CHEM GES FUR FLUGCHEM ANTRIEBE MBH
  • EP2048344B1 patent drawingFigure 1~5

AI summary

The engine has a thrust nozzle (2), a combustion chamber, and thermal insulations (3, 4) between a metallic external structure (1) and the nozzle and/or the chamber. The insulations have a metallic external coating, and modules with a circle-arc-shaped cross section and the metallic external coating. The insulations have a layer of a micro-porous insulating material that is provided with a fiber coating. A layer of textile sheet material made of ceramics and/or carbon fibers is arranged between the micro-porous insulating material layer and the coating on an inner side of the material layer.