ULB research| Personal data | Research themes | Ongoing teaching | Publications |
ATASI Omer
Units
TIPs - Transport phenomena and process engineering
The objective of the research carried out at the Transfers, Interfaces and Processes (TIPs) laboratory of the Université libre de Bruxelles (ULB) is the experimental characterization and the mathematical modeling of transport phenomena within systems containing several phases (gas and/or liquid and/or solid), exchanging matter, heat or momentum, through an interface between these phases, at scales between the micron and the millimeter. The research carried out revolves around mainly fundamental and/or generic questions. They have direct applications in the fields of health, environment, heat transfer technologies and agro-food, chemical, microtechnology, materials and space industries. Our current research concerns 9 scientific topics: Drying, Enzymatic processes, Evaporation and boiling, Gas-liquid transfers, Microfluidics, Physiological fluids, Soft/Wet microrobotics, Surface rheology and, as a side research area, the characterization of Ancient hydraulic systems. The TIPs laboratory is composed of 5 professors and approximately 35 researchers. It is divided into two research units : "TIPs - Transport phenomena and process engineering" and "TIPs - Fluid physics". The TIPs laboratory collaborates with a number of scientific and industrial partners in Belgium, Europe, USA, Israel and Canada, in the frame of several networks funded by the European Commission or by the European Space Agency, and also thanks to support at National level (BELSPO, FNRS, Brussels and Walloon Regions). The team investigates mostly fundamental and/or generic questions, i.e. common to several natural or industrial processes. Studied problems most often involve notions of nonlinear dynamics, physical chemistry (equilibrium and non-equilibrium), statistical mechanics, transport phenomena, applied mathematics, ... The used tools are either theoretical (stability analyses, scaling laws, asymptotic techniques, ...), numerical (commercial or 'home-made' software), or experimental (fluid behavior visualization by interferometry, Schlieren, infrared thermography, ...). The TIPs laboratory has an experimental facility devoted to the realization, the characterization and the manipulation of systems including several phases (gas and/or liquid and/or solid), exchanging mass, energy or momentum, at a characteristic length scale between the micron and the millimeter. The lab is part of the Micro-milli platform. It is managed by Adam Chafaï, PhD.
At the TIPs (Transfers, Interfaces and Processes) Department of ULB, the main goal of the ongoing research is to develop new theoretical, numerical and experimental methods allowing to understand and predict the behavior of multiphase systems, and to design or optimize industrial processes dedicated to the transformation of matter (mineral, organic or biological) and energy. There are essentially six main research themes : mixing, gas-liquid mass transfer, dynamics of interfaces and their instabilities, wetting, porous media, heat transfer and phase change (evaporation, crystallization, ...). The Department is made of two complementary research units : the Fluid Physics Unit and the Chemical Engineering Unit. The Fluid Physics Unit collaborates with a number of scientific and industrial partners in Belgium, Europe, USA, Israel and Canada, in the frame of several networks funded by the European Commission or by the European Space Agency, and also thanks to support at National level (BELSPO, FNRS, Brussels and Walloon Regions). The team investigates mostly fundamental and/or generic questions, i.e. common to several natural or industrial processes. Studied problems most often involve notions of nonlinear dynamics, physical chemistry (equilibrium and non-equilibrium), statistical mechanics, transport phenomena, applied mathematics, ... The used tools are either theoretical (stability analyses, scaling laws, asymptotic techniques, ...), numerical (commercial or 'home-made' software), or experimental (fluid behavior visualization by interferometry, Schlieren, infrared thermography, ...).
Projetcs
In this research project, we aim to describe the transport phenomena (mass and momentum) taking place inside and around a bubble/drop within a gas-liquid contactor. By combining theoretical (balance equations, stability analysis, asymptotic techniques...), numerical (commercial codes, “home-made” codes) and experimental tools (essentially implementing optical diagnostic techniques: shadowing or interferometry), we can obtain original results, related for example to the dynamics of bubbles in microchannels (paying a special attention to the inertial and capillary migration forces, as well as to the role of surfactants.), the dynamics and morphology of unconfined ellipsoidal bubbles or the coupling between flow, bubble-liquid or gas-droplet mass transfer and chemical reaction. Selected publications : Atasi, O., Haut, B., Pedrono, A., Scheid, B., & Legendre, D. Infuence of soluble surfactants and deformation on the dynamics of centered bubbles in cylindrical microchannels. Langmuir (published online). 2018 Rivero-Rodriguez, J., & Scheid, B. Bubble dynamics in microchannels: internial and capillary migration forces. Jounal of Fluid Mechanics, 842, 215-247. 2018 Mikaelian D., Haut B., & Scheid B., Bubbly flow and gas-liquid mass transfer in square and circular microchannels for stress-free and rigid interfaces: dissolution model, Microfluidics & Nanofluidics, 19, 899-911. 2015 Mikaelian, D., Larcy, A., Cockx, A., Wylock, C., & Haut, B. Dynamics and morphology of single ellipsoidal bubbles in liquids. Experimental Thermal and Fluid Science, 64, 1-12. 2015
