Coupling Eulerian interface capturing and Lagrangian particle methods for atomization simulation

The study of the liquid jet’s atomization consisting of two immiscible phases is a fundamental research subject. The main motivations linked to the study of these phenomena are the numerous applications resulting from them. For example, in the study of the propagation of a spray within a combustion chamber or for pharmaceutical applications. Their study is carried out by a theoretical, experimental and numerical approach. Each of these techniques faces its own limitations: in the numerical study, the treatment of the droplets resulting from the jet break is a limiting factor due to the size ratio introduced. This thesis manuscript presents the coupling between an Eulerian interface treatment method and a Lagrangian particle transport method, proposing a multi-scale approach to atomization. The numerical solver Archer is used to transport a two-phase flow and to study its evolution, solving the incompressible Navier Stokes equations. The interface separating the two phases is represented by a method combining precision and robustness, the Volume of Fluid/Level-Set coupling. The discretization of the Navier Stokes equations and the transport of the interface is presented in the first part of this manuscript. This introduces the weaknesses of this method due to the multi-scale aspect of the atomized jets: the low precision of the transport of the drops resulting from the secondary atomization. The second section of this manuscript is dedicated to the introduction of Lagrangian drop transport, different approaches are implemented and validated within the computational code Archer. Then, the coupling between the Eulerien and Lagrangian solver, validated from numerical experiments, is introduced. The latter aim to present the methodology implemented to validate the coupling while respecting the conservation of time and mass. This method is then applied to academic cases to introduce the parameterization allowing the junction between the Eulerien and Lagrangien solvers. Finally, the developed method is applied to the study of an atomized jet of crossflow configuration, used in gas turbine or ramjet. The results obtained demonstrate the possibilities related to the Eulerien/Lagrangien coupling, both on the physical and numerical aspects, opening up a model of drop breakup under Lagrangien transport.