CBL - Campus del Baix Llobregat

Projecte llegit

Títol: Numerical simulation of fluids in microfluidics (microgravity conditions) with OpenFOAM

Estudiants que han llegit aquest projecte:

Director/a: ARIAS CALDERÓN, SANTIAGO

Departament: FIS

Títol: Numerical simulation of fluids in microfluidics (microgravity conditions) with OpenFOAM

Data inici oferta: 21-07-2022     Data finalització oferta: 21-03-2023


Estudis d'assignació del projecte:
    GR ENG SIST AEROESP
Tipus: Individual
 
Lloc de realització: EETAC
 
Paraules clau:
Microgravity, Two-phase flows, T-junction, Computational Fluid Dynamics (CFD), OpenFOAM
 
Descripció del contingut i pla d'activitats:
Two-phase flows (a mixture of two-fluids, like liquid/liquid or gas/liquid) are frequently found in all kinds of common on-ground applications (carbonated beverages, food, cosmetics, etc), but also in sophisticated space systems, such as space engines, bioreactors, thermal systems, life support systems, etc. Gas/liquid-based systems, lighter than the classical liquid/liquid systems, suppose an evident economic benefit for spatial applications. And yet, despite their benefits, the generation, regulation and control of two-phase flows is not yet fully understood, and some fundamental questions remain open.

Numerical simulations, or Computational Fluid Dynamics (CFD) studies, are a very powerful way of approaching the study of two-phase fluids. CFD allows modifying all the physical parameters involved in the problem, becoming a more flexible option than real experiments. In this TFG, the student will work with OpenFOAM, an open source CFD software of enormous versatility.
 
Overview (resum en anglès):
During the past decades, interest in droplet-based microfluidics has substantially increased due to its wide range of applications, such as biochemical analyses or material synthesis. Therefore, it is essential to predict and understand these droplets¿ generation mechanisms to control their size and, eventually, design the precise devices to produce them.
This work presents numerical simulations of two phases of liquids in a rectangular T-shaped microchannel with a neck under microgravity conditions. The study will be made following the same scenario as the scientific paper [1], to do a trustworthy comparison between the two of them and verify the obtained results. Consequently, the liquids used will be deionized water for the dispersed phase and sunflower oil for the continuous one.
The software utilised to carry out these numerical simulations was OpenFOAM. The chosen solver was InterFOAM, which is ideal for two incompressible, isothermal and immiscible fluids; considering that it uses the Volume Of Fluid (VOF) method. To process the obtained data, ParaView and Excel were used as well.
Many parameters were modified and taken into account when performing the simulations until the perfect fit was found, such as the boundary conditions, the mesh quality or the microchannel length. After that, the main selected variables to analyse were the diameter, the volume and the velocity of the generated droplets.
Finally, the study concludes that the results obtained during the simulations are not in good agreement with the literature, obtaining significant errors in the droplets volume. Moreover, the produced number of droplets is bigger than the expected. Taking all this into account, it is not possible to say that the Computational Fluid Dynamics (CFD) method is an accurate one when we aim to perform this type of experiment.

© CBLTIC Campus del Baix Llobregat - UPC