CBL - Campus del Baix Llobregat

Projecte llegit

Títol: Simulations of two-phase flows in space conditions (microgravity) with the numerical solver OpenFOAM

Estudiants que han llegit aquest projecte:

Director/a: ARIAS CALDERÓN, SANTIAGO

Departament: FIS

Títol: Simulations of two-phase flows in space conditions (microgravity) with the numerical solver OpenFOAM

Data inici oferta: 29-06-2018     Data finalització oferta: 28-02-2019


Estudis d'assignació del projecte:
    GR ENG SIST AEROESP
    MU AEROSPACE S&T 15
Tipus: Individual
 
Lloc de realització: EETAC
 
Paraules clau:
Two-phase, Spatial conditions, Microgravity, Numerical simulations, OpenFOAM, Microfluidics, Bubble generation
 
Descripció del contingut i pla d'activitats:
Fluids behave differently in space than in terrestrial
conditions. These behaviors can be sometimes surprising and even
dangerous for the good performances of the onboard subsystems of
space vehicles such as space launchers or satellites. The main goal
of this TFG/TFM is to study some of these phenomena by means of
numerical simulations. OpenFOAM, an open source software, is the
solver used for this study.
 
Overview (resum en anglès):
Microgravity is the condition perceived in an object or body when gravity effect is negligible.
This can mostly happen when the object is in a constant free fall state, which gives
the false perception of Zero Gravity. It being useful to study for space applications or
small-scale applications like microfluidics.
In this project, we work with numerical simulations to study the bubble generation in
microgravity conditions inside a T-junction channel. The simulations are made through
open source softwares like OpenFOAM, which performs them; and ParaView, which is
responsible of the post-processing and the visualization of the problem. The solver chosen
from OpenFOAM is interFoam since it treats the multiphase fluid of our simulations as
incompressible, immiscible and isothermal in a Reynolds laminar region.
Before generating results, the methodology of this project implies generating the
mesh, get to detach bubbles with the correspondent conditions [1] and perform convergence
tests for the mesh, the time step and the contact angle at the mesh walls. The
goal of the convergence tests is to use the most convenient mesh possible to obtain good
results and a small time step to be close to convergence without extra computational cost.
The contact angle allows us to determine which fluid sticks to the wall the most and how
this is done.
The results are divided in two parts. From one hand, we measure the pressure at
four points around the junction of both pipes to see its evolution when a bubble is formed.
On the other hand, with the chosen mesh, time step and contact angle; we combine
different inlet velocities for both fluids to see how the bubble parameters change at their
detachment. The change in these parameters makes us justify if the bubbles behaviour is
adequate and close to the real physical behaviour.
In the end, the methodology has been followed at all times, but some stages of it
have taken extra time or have presented challenges that produced larger errors in our
results. Even so, despite the causes of these errors, the analysis of the results and
behaviours have been made in a similar way as expected.



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