Simulation numérique de l’écoulement dû à une réaction chimique dans les systèmes non isothermes liquides-liquides

Abstract

In this work, a two-dimensional numerical analysis of the unstable state of an reactive system of two immiscible, non-isothermal liquid layers filling a reactor formed by two parallel glass plates, called Hele-Shaw cell, vertically disposed, in the gravity field, has been achieved. We are interested in the general behavior of the chemo hydrodynamic instability generated by the coupling of a neutralization reaction between an acid and a base and the instabilities induced by buoyancy in a Hele Shaw cell. The temporal evolution of the instability and the verification of the effects: (1) of the ratio of the initial acid / base concentrations, (2) of the space between the two plates of the cell (3) of the gravity and (4) of the chemistry, on the structure of the flow produced in the cell and on the advancement of the convection fingers, not forgetting the determination of the velocity, concentration and temperature profiles, were the primary objectives of the thesis. The mathematical model governing the phenomenon was solved numerically by the CFD software COMSOL MultiPhysics based on the finite element method and a validation of the calculations by making a comparison with the experimental data was performed. The results obtained show that this numerical tool is promising for the good understanding of the reactive instabilities which occur when two immiscible fluids come into contact.