PhD vacancy in Universiteit Gent (4 years) - Simulation and testing of short fibre-reinforced composites for application in heat exchangers

Almost all heat exchangers are currently made of metal. A few attempts have been made to make heat exchangers from (fibre-reinforced) polymers. Switching from metal to polymer/composite can have several advantages:

• The copper price has increased a lot over the last years, and economical alternatives in polymer might be feasible
• In corrosive environments (chemical sector, toxic gases, contaminated fluids), metals do not survive
• For domestic applications, the weight of HVAC systems could be strongly reduced, making it possible for a single man to carry the heat exchanger to the desired location in the house

Two major drawbacks of polymer/composite heat exchangers are (i) their limited temperature stability, and (ii) their bad thermal conductivity. By adding conductive fibres to the polymer, the temperature-dependent mechanical properties and thermal conductivity could be improved. Due to the envisaged processing methods, short fibres are more likely to be used than continuous fibres. Up till now, the research on composites for heat exchangers has hardly been explored, and there is a vast potential for attractive applications. Ghent University has been awarded a 4-year research project with 3 UGent research groups involved (groups of thermodynamics, polymer processing and mechanics of composites). There is a large interest from industry as well, who have defined the demonstrators that have to be built at the end of the project. Finally, there is a strong spill-over possible to automotive industry, where short fibre-reinforced composites are used in "under the hood" applications, components close to the engine, exhaust or other high-temperature regions. Their mechanical stability and fatigue performance are crucial properties to predict. Our research group has 1 postdoctoral research fellow for 3 years, and 1 PhD for 4 years. The PhD student will concentrate on the simulation and testing of short fibre-reinforced composites for application in heat exchangers. The tasks consist of:

• design of a fatigue test set-up for elevated temperatures/pressures
• fatigue experiments on short fibre-reinforced composites under realistic loading conditions for heat exchangers
• static simulations of hot-spot areas in the heat exchangers under thermomechanical loading
• development of a predictive model for fatigue performance of the short fibre-reinforced composite

The PhD student will be assisted by a postdoctoral research fellow (vacancy #2). The research group has also a wide expertise in fatigue testing and finite element simulation at coupon and structural level.

Desired skills and experience

Only candidates with a Master degree should apply. The candidate should have a strong background in experimental mechanics of materials, preferably combined with knowledge in simulation of composite materials and fatigue.

About the employer

The "Mechanics of Materials and Structures" research group at Ghent University (UGent-MMS) has 30 years of experience in mechanics of materials (in particular composite materials), and almost 20 years in finite element modelling and computational mechanics. The mechanical behaviour is studied under static and dynamic loading conditions, where dynamic loading ranges from (high) dynamic impact over vibrations till fatigue. For investigating these loading regimes, the group has a wide range of experimental facilities. Additionally, the experimental tests are equipped with a variety of non-destructive techniques. Research is running on the use of optical fibre sensors, ultrasound, digital moiré techniques and digital image correlation. Further, the group has a strong tradition in numerical modelling, in particular in finite element codes. The emphasis lies on the correct modelling of mechanics and damage phenomena observed in composite materials during testing. Therefore dedicated material models or constitutive laws are developed and integrated into finite element simulations. Validation is done through comparison with instrumented experimental tests.
For the moment, about 30 researchers are active in the group. For more information CLICK