Implementation and investigation of subgrid-scale models in particle-laden flows

The master thesis project concerns the particles behaviour in a turbulent multiphase flow and it was conducted at the Institute of Aircraft Propulsion Systems (ILA) of the University of Stuttgart. To perform Large-eddy simulations (LES) of particle-laden flows the open-source solver FLEXI developed at the Institute of Aerodynamics and Gas Dynamics (IAG) is used. In the context of LES, subgrid-scale (SGS) models are required in order to approximate the unresolved scales of the fluid phase on the particle motion. To investigate the particle behaviour the two SGS models of Sommerfeld and Minier et al. are implemented and validated in FLEXI. Therefore, the model of Breuer et al., previously implemented, is used as well. The performance of these models are evaluated through simulations of a particle-laden flow in a round-jet. First, the numerical results are compared against the experimental data of Fan et al. It was found that due small differences in the setting of the simulations the numerical results are and characterized by a higher spreading of the particles and smaller turbulent kinetic energy. Second, to further evaluate the performance the SGS results are compared with the simulation in which no SGS model is employed. In the end only minor differences are visible between the simulations, in which all the quantities analysed for each SGS model are characterized by the same trend.