Development and validation of a 2D Vortex Particle-Mesh method for incompressible multiphase flows

The motivation of the present thesis is to assess the potential gains that Vortex Particle-Mesh methods could bring to numerical simulations for the nuclear industry, and in particular to pool-type reactors using heavy liquid metal coolants. One such reactor is the Belgian MYRRHA Gen IV prototype reactor. Indeed, the flow taking place within the vessel (i) tends to be highly-advective and (ii) has local sources and sinks of momentum that generate global motion of the coolant in much greater volumes. Those conditions makes the use of Vortex Particle-Mesh method potentially attractive. The present thesis develops a Vortex Particle-Mesh method for multiphase flows with heat transfer. Starting from an existing VPM solver for single phase flows, features are added (such as level set or smeared interface methods), numerical difficulties are studied and solutions to the latter are proposed. The correctness of the resulting VPM solver is assessed on popular CFD benchmarks, and its performance both in terms of accuracy and computational efficiency is compared to the one of a traditional velocity-pressure solver. Eventually a case of study similar to those that could be encountered in nuclear reactors is run to demonstrate the relevance of the solver for industrial flows.