Research Spotlight: Luxembourg’s European research university – a dynamic driving force behind an innovative country

University of Luxembourg at a Glance

• With students originating from 110 countries, academic staff from 20 countries as well as 78 partner universities around the globe, “internationality” is probably one of the qualifiers which characterises us best. In fact, we need internationalism, especially to organise the mobility of our students. This is particularly important since all of our Bachelor students study at least one semester abroad. Furthermore, the University of Luxembourg has several cross-border, bi- or tri-national Bachelor and Master degrees and a part of its PhD candidates work towards a joint or double PhD degree.
• The three languages we use, several Master programmes in reference to Europe, the background of our personnel and the country, as well as adjunct staff coming from many European institutions, make us more European than most other universities.
• In 2014, the University of Luxembourg raised 32.27 million Euros of external research funds derived from the European Union, the National Research Fund (FNR), endowed chairs and other partners. In the same year, our researchers have published a total of 1,098 scientific works. With 569 PhD doctoral candidates, doctoral research contributes strongly to our research output as well.
• Interdisciplinary approaches are gradually becoming a dominant feature of our research activity: two interdisciplinary centres (Security and Trust, Luxembourg Centre for Systems Biomedicine), a National Research Fund-PEARL grant combining chairs in Sociology and Economy, the chair funded by satellite operator SES in Space law as well as cross-disciplinary teaching modules for our students are telling examples thereof.

Advanced Multi-physics Simulation Technologies at University of Luxembourg

A vast number of engineering applications include not solely physics of a single domain but consist of several physical phenomena, and therefore, are referred to as multi-physics. As long as the phenomena considered are to be treated by either a continuous, i.e. Eulerian, or discrete, i.e. Lagrangian approach, a homogeneous numerical solution concept may be employed to solve the problem. However, numerous challenges in engineering exist and evolve that include a continuous and discrete phase simultaneously, and therefore, cannot be solved accurately by continuous or discrete approaches only. Problems that involve both a continuous and a discrete phase are important in applications as diverse as the pharmaceutical industry, e.g. drug production, agriculture food and processing industry, mining, construction and agricultural machinery, metals manufacturing, energy production and systems biology. Some predominant examples are coffee, corn flakes, nuts, coal, sand, renewable fuels, e.g. biomass for energy production and fertilizer.

The Lu(xembourg)XDEM research team develops advanced simulation technology for multi-physics applications including the abovementioned ones. For this purpose the Extended Discrete Element Method (XDEM) extends the dynamics of granular materials or particles as described through the classical discrete element method (DEM) by additional properties such as the thermodynamic state, stress/strain, or electromagnetic field for each particle. XDEM additionally evaluates properties such as the internal temperature and/or species distribution within each particle, so that the sum of all particle processes characterises the global behaviour. These predictive capabilities require an interaction to fluid flow by heat, mass and momentum transfer and impact of particles on structures, and thus couples to Computational Fluid Dynamics (CFD) and the Finite Element Method (FEM).

All software modules are embedded into a well-designed, object-oriented hierarchy that relieves the user of underlying mathematics or software design, who is therefore able to direct his focus entirely on the application. These capabilities helped us to develop the following strategic competencies:

A relevant example is drying of biomass as a porous and a renewable fuel that has gained considerable attraction due to its neutral carbon footprint. Obtained results for both temperature and residual water mass fraction within a wet wood particle, as shown in the figure below, allow a detailed estimation of the drying rate, e.g. drying period.

Distribution of temperature and residual water mass fraction versus radius and time during drying of a porous wood particle showing a drying front propagating through the particle.

This concept allows tracking the drying process of each particle, for example, on a forward acting grate. Hence, the total length of the grate to achieve drying is estimated before expensive prototypes are built.