Ongoing research projects

IMMC

Ongoing research projects in iMMC (December 2022)


This a short description of research projects which are presently under progress in iMMC.
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Biomedical engineering

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Fluid mechanics

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List of projects related to: two-phase flows




Numerical Modeling and Simulation of Sediment Mobilisation and Transport due to Turbulent Currents
Researcher: Anouk Riffard
Supervisor(s): Miltiadis Papalexandris

The proposed doctoral research evolves around two principal axes. The first one is the development of mathematical models and algorithms for flows of fluid-solid particles mixtures, i.e. granular suspensions. The second one is the use of these algorithms for the study of sediment mobilisation and transport due to turbulent currents.



Development of high-fidelity numerical methods for the simulation of the aerothermal ablation of space debris during atmospheric entry
Researcher: David Henneaux
Supervisor(s): Philippe Chatelain

This project, lead in collabaration with the von Karman Institute (VKI) and Cenaero, aims at developing high-fidelity numerical methods for the simulation of the aerothermal ablation of space debris during an atmospheric entry.

The number of space debris orbiting the Earth is becoming increasingly problematic for the integrity of operational satellites and the future access to space. The many space debris mitigation projects currently under study require an accurate prediction of the degradation of these objects when they re-enter the atmosphere in order to comply with the severe re-entry safety requirements.

Dedicated engineering softwares are used to assess the survivability of these debris. However, the correlation-based models implemented in these software lack accuracy and they do not allow to gain insight into the complex flow phenomena taking place near the surface of the body, yet essential for the conception of new satellites designed for demise. That is why CFD methods are needed to study this complex situation. But the methods currently available rely on simplifying assumptions that compromise the reliability of the results.

The objective of this project is to develop new high-fidelity numerical methods able to deal with the presence of the three phases in the same domain and their complex interactions. They will be grouped into the ARGO code under development at CENAERO, VKI, and UCLouvain, which relies on the discontinuous Galerkin method. To do so, a highly-accurate multiphase method coupled with evaporation and surface tension models and based on a sharp interface approach will be employed for the treatment of the gas-liquid interface, while a state of the art melting method accounting for the diffuse character of the liquid-solid interface will be considered. Both methods will be built to work with multicomponent compressible equations. The code will then be validated with experimental data from the VKI Plasmatron facility.



2-phase CFD simulations of electrolyte-bubble interactions during alkaline water electrolysis
Researcher: Kevin Van Droogenbroek
Supervisor(s): Joris Proost

In today’s world, concern is growing about the future of energy. Despite very ambitious international climate goals by 2050, global energy-related carbon dioxide (CO2) emissions keep increasing. In order to tackle this problem, hydrogen (H2) seems to be the right solution since it is a way to produce, store, move and use energy in a clean way. However, 95% of the actual hydrogen production is made of grey hydrogen, e.g. H2 produced from fossil energies, which leads to high CO2 emissions in the atmosphere. One way to decarbonise this energy vector is to produce green hydrogen by means of renewable energies (solar panels, wind turbines, etc). This is where my research project funded by the Walloon region comes in, focusing on the production of green hydrogen by alkaline water electrolysis (AWE).

In general, AWE is characterised by the use of two planar electrodes separated by a certain distance and operating in a liquid alkaline electrolyte solution (e.g. KOH, potassium hydroxide). However, the efficiency of the process can be improved by the use of 3D electrodes in a zero-gap cell configuration. This configuration is the one that will be used in the scope of this research and it is depicted in Figure 1. The chemical reactions taking place at the cathode and at the anode are also highlighted.

More specifically, the work will consist in the fluid mechanical modeling of liquid and gaseous flows within alkaline electrolysis cells filled with 3D porous structures. The study of liquid electrolyte flow and of gaseous hydrogen bubble formation and escape will allow to optimise the performance of the electrolyser. Computational Fluid Dynamics (CFD) is a powerful numerical tool that will be used during this project to determine the optimal flow parameters required to homogenise the electrolyte flow (to take advantage of the full specific area provided by the electrodes) while favouring hydrogen bubbles removal from the electrolysis cell (to avoid bubble entrapment within the complex 3D structure).

As an example, the added value of a numerical simulation for a better understanding of the electrolyte flux distribution within an empty cell (e.g. without 3D structure) is shown in Figure 2. The velocity field of the electrolyte (in m/s) was simulated on the OpenFOAM software. Note that the geometry of the cell corresponds to the one of the pilot electrolyser used at UCLouvain (see Figure 3).