Abstract
Three-dimensional direct numerical simulation is performed in a particle-laden turbulent mixing layer to investigate the effects of a parcel modeling on the characteristics of particle dispersion, scalar diffusion and velocity fluctuation. The effects of the parcel model are carefully investigated and discussed in comparison with the case in which the parcel model is not used as a reference, RC, in terms of the number of particles represented by a parcel, Np, and Stokes number defined by the particle relaxation time and Kolmogorov time scale, St. Results show that the parcel model can capture almost behavior of particle dispersion while the discrepancy between the model and RC becomes larger with increasing Np. The evaporation rate is suppressed by employing the parcel model, because the vapor pressure in a cell is rapidly saturated by the parcel which represents a number of particles and subsequently the mass transfer number is underestimated. The trend of turbulence modulation is qualitatively captured by the cases employing the parcel model with the small Np while the case with the larger Np and St cannot capture the trend. It is therefore essential that Np and St are carefully determined to avoid capturing the nonphysical behavior in a numerical simulation with the parcel model.
