High Temperature High Performance Composites

17th April 2012

Joe Mills-Brown

Supervisors: Kevin Potter, Steve Foster and Tom Batho

www.bris.ac.uk/composites

Presentation Outline

• Project background and aim

• Requirements

• Objectives

• Completed work

• Current work

• Future work

Project Background and Aim

Background

• High temperature environments in both motorsport and aerospace applications can be exploited for performance gains, including the drive for compaction of components and systems closer to heat sources

• Temperatures up to 1000°C are encountered

• The trend is set to continue and the large temperatures highlight the potential for heat energy recovery

• Current solutions are costly, offer poor durability and little mechanical performance

• Can we do better?

Aim

• Evaluate and characterise suitable composite materials

• Exploit novel composite materials and concepts to create thermal structures and systems

• Investigate harvesting, storage and use of thermal energy

Objectives

1. Materials and Structures

2. Testing and Modelling

3. Thermal Energy

Harvesting

• Requirements;

– High temperature stability (up to 1000°C)

– Low density

– Low lead time

– Good mechanical properties

– Ability to form complex geometries

• Suitable materials are very limited, but composites hold the answer

• Ceramic composites meet some requirements but fail in others

• Polysialates;

– Ceramics cured through polymerisation

– Also known as geopolymers or inorganic polymers

– Carbon or SiC fibre reinforcement

– Meet all requirements but little is known about their performance

Requirements

Requirements

• Focus on polysialate composites

• Characterisation;

– Mechanical

– Thermal

– Physical

• Hybrid structures and engineering systems envisioned

1. Materials and Structures

Hybrid Structural Solution

CMC’s and PMC’s

Cores Coatings

Adhesives

Modelling Testing

2. Testing and Modelling

Validation

Material Data

650°C

300°C 150°C

• Thermal properties;

– Thermal conductivity

– Specific heat capacity

– CTE etc.

• Mechanical properties;

– Stiffness

– Strength etc.

• How do the properties change with temperature?

• Thermal shock and fatigue, not well understood

• Replicate in-service conditions

• Analytical; approximate

• FE modelling; refinement

• Heat transfer;

– Flow through materials

– Radiating heat sources

– Forced and free convection

• Thermo-mechanical response of structures

• Will make up the latter stages of the project

• Large potential given the temperatures available – 1000°C

• Can we recover and exploit this energy?

3. Thermal Energy Harvesting

• What technologies are available?

• Validation and sizing

• Proof of concept

• Identification of primary materials

• Complete thermal property characterisation up to 1000°C

• Microstructure investigation

• Evaluating project background

• Extensive literature review

• Thermal shock experiment design

• High temperature tensile test design and manufacture

• Identification of tests to replicate in-service thermal conditions

• Heat transfer modelling

Completed Work

Obj.2

Obj.1

Current Work

• High Temperature tensile testing rig;

– Characterisation

– Testing

• Thermal shock testing

• Combined heat transfer and mechanical load modelling

• Case study – draws on test results and modelling experience and applies to real world problem

• Identification of case study;

– Background

– Heat transfer modes

– Boundary conditions

– Analytical model inputs

Obj.2

30°C

650°C 25°C

240°C

1 minute

20 minutes

Incoming; forced convection heat flux

Outgoing; radiation and free convection

Future Work

• High temperature mechanical testing

• Thermal shock experiment

• Case study

• Evaluation of polysialate composites for these applications

• Design methodologies

• Investigation of other structural materials;

– Cores

– Adhesives etc. Obj.1

Obj.3

Obj.2

• Thermal energy harvesting;

– Available technologies

– Validation and sizing

– Incorporation into composites

High Temperature High Performance Composites

Questions?

Email: J.Mills-Brown@bristol.ac.uk

Tel: 0117 3315651

www.bris.ac.uk/composites