Modeling particle distribution in a ventilated room with modified discrete random walk methods

Abstract

Abstract The airflow and micro-particle dispersion in a 3-D ventilated scaled room has been simulated numerically. The flow field was studied by the Eulerian method using a Reynolds Averaged Navier-Stokes model, and we used the Lagrangian approach to solve the equations of particle motion. The purpose is to evaluate and compare various discrete random walk methods (DRW) and continuous random walk methods (CRW) to evaluate particle concentration distribution in indoor environments. The isotropic DRW method’s performance has been compared with models in which anisotropy of turbulence is applied, including CRW and modified DRW models based on near-wall direct numerical simulation results, near-wall kinetic energy, and the helicity of the flow. The results reveal that the isotropic DRW method can predict particle concentration in the indoor environment, and using a modified DRW model is not necessary. HIGHLIGHTS We have examined the performance of the isotropic DRW stochastic model in predicting the concentration of suspended micro-particles in a ventilated room. Three modifications of isotropic DRW models, based on near-wall DNS Particle concentration results of modified DRW models based on helicity, have also been investigated. The modified DRW model, based on near-wall DNS results and the CRW model, does not have a good performance for concentration prediction in a ventilated room. The modified DRW model based on helicity and near-wall kinetic energy has good agreement with experimental data.