Simulations of indoor airflow and particle dispersion and deposition by the lattice Boltzmann method using LES and RANS approaches

Publication date: June 2016
Source:Building and Environment, Volume 102
Author(s): H. Sajjadi, M. Salmanzadeh, G. Ahmadi, S. Jafari
In this paper the Lattice Boltzmann method (LBM) in conjunction with the large eddy simulations (LES) and Reynolds Averaged Navier–Stokes (RANS) models was used to study the airflow and particle dispersion and deposition in indoor environments. The turbulent airflow was simulated first using the LES in framework of LBM, in which the sub-grid scale turbulence effects were simulated through a shear-improved Smagorinsky model (SISM). The airflow was also simulated using the k−ε turbulence model within the framework of LBM by the addition of two populations for the turbulence kinetic energy, k, and the dissipation rate, ε. The present simulation results for the airflow showed good agreement with the experimental data and the earlier numerical results. To simulate the particle dispersion and deposition in the room, particles with diameters of 10 nm–10 μm were investigated. For generating the instantaneous turbulence fluctuations for thek−ε model, the discrete random walk (DRW) method was used. Effects of SGS turbulence fluctuation on deposition rate of different size particles were also studied. It was shown that inclusion of the SGS turbulence fluctuations improves the model predictions. The simulated results for particle dispersion and deposition showed that the predictions of the present method are quite similar to the earlier finite volume method and are in good agreement with the experimental data.