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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
• 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: [email protected]
Tel: 0117 3315651
www.bris.ac.uk/composites