Virtual Seminar"Intensification of mass transfer using active and passive methods"Eliane Younes


Thursday, August 4, 2022 - 16:00




Micro/Bio/Nanofluidics (Shen) Unit would like to invite you to the virtual seminar by Dr. Eliane Younes on August 4 (Thursday).
Date: August 4, 2022
Time: 4:00-5:00PM
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Meeting ID: 938 7314 8807
Passcode: 097777


Eliane Younes
Education, Research and Innovation center - Energy and Environment CERI EE IMT Nord Europe, France


Intensification of mass transfer using active and passive methods


Many industrial applications require intensification of mass/heat transfer in order to increase the efficiency of energy systems and processes such as refrigeration systems, air conditioning systems, food processing systems, petrochemical systems, etc.
There are two types of methods that can be used to increase mass/heat transfer: active and passive methods, depending on whether a specific energy input is required or not. The first study concerns the active method. It consists of proposing a new continuous active mixer for viscous fluids. This mixer uses the chaotic advection as mixing mechanism considered to be efficient for mixing such fluids. The flow characterization is performed for Newtonian and yield stress fluids using velocity field measurements (PIV) and mixing patterns (LIF). We show, for the Newtonian fluid case, that the flow is more chaotic and the mixing is more homogeneous for an optimal choice of control parameters for which the fluid particles are held longer in the mixing zone and are subjected to more stretching and folding operations. In the case of a yield stress fluid flow, we show that the presence of yield stress alters the flow topology and reduces the efficiency of the stretching and folding mechanism, leading to a deterioration of the mixing quality.
The second study focuses on the passive intensification of mass transfer in an air flow in a channel equipped with a vortex generator. The objective of this study is to characterize the transition to turbulence. Using instantaneous velocity measurements (LDA), a frequency analysis is performed. This study allows the detection of the onset of flow instability and the understanding of flow behavior in the transitional regime. For the turbulent flow regime, the turbulence characteristics are determined and show an exponential decrease of the turbulence dissipation rate with the distance from the vortex generator.



In 2012, I started my studies at the Engineering Faculty of the Lebanese University (LU). In 2016, I was selected to participate in the double degree program between the Lebanese University and École Centrale of Nantes (ECN). I moved to France and in 2017, I obtained a MSc in mechanical engineering from the LU and a MSc in Energy from the ECN. Following this, I joined the Heat Transfer and Energy Laboratory of Nantes (LTeN, France) on a grant from the national research agency, and obtained my PhD from University of Nantes in 2020. Then, I worked as a teaching and research assistant at Polytech’ Nantes and the LTeN. In December 2021, I joined IMT Nord Europe as a Postdoctoral researcher.
My research focuses on the characterization of complex flows using optical techniques (PIV, SPIV, LDA, LIF, microscopy). This complexity is due to the flow regime ( chaotic advection, transition to turbulence), the geometry (obstacles, small scale) and the rheological behavior of the fluid. My PhD focused on chaotic mixing of Newtonian and yield stress fluids. I also worked on rheological characterization of yield stress fluids, wall slip characterization during microscopic flows of yield stress fluid and visualization of Carbopol gel microstructures. Currently, I am working on air flow characterization in a wind channel equipped with a vortex generator in different flow regimes.


Prof. Amy Shen

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