Aerosol nucleation in a turbulent jet using Large Eddy Simulations

This work presents a model for particle nucleation and transport in the context of Large Eddy Simulation. A turbulent Dibutyl-Phthalate-laden Nitrogen jet diffusing in atmospheric air is used for validation. The proposed nucleation model treats the process in a probabilistic manner where the frequency of events is determined from local equilibrium conditions. Two methodologies for the sub-grid influence on nucleation rates are implemented: the presumed β-PDF and the source expansion method. Good agreement is found with respect to the experimental results for particle concentrations. The differences between using mean and instantaneous values for the evaluation of the nucleation rate are shown. For the grid spacing used, the unresolved scales seem to have little influence on the calculated particle concentrations. It is concluded that the use of instantaneous nucleation rates is advantageous and therefore it is important to consider a particle coupling that allows for the full use of instantaneous values.