Lattice Boltzmann method for understanding the mass transfer mechanisms of two-phase organic indoor-air pollutants

The mass-transfer of Semi-volatile organic compounds (SVOC) pollutants in indoor air with suspended particles is so complicated that traditional experimental methods are difficult to reveal the mass-transfer mechanism. This paper employs Lattice Boltzmann Method (LBM) with a source term of the gas/particle interaction to study SVOC mass transfer behaviors of two-phases SVOC pollutants. LBM is used to simulate fluid flows and SVOC mass transfer. The cell automation (CA) probabilistic model is applied to simulate particle motion. Firstly, one particle is simulated to focus on particle-phase concentrations, then a large number of particles are simulated to focus on the particles' effects on the SVOC concentration field. Results show: i) the particle-phase concentration calculated from the equilibrium model is tremendously larger than from the dynamic model; ii) in addition to removing SVOC from indoor air, particles also help gas-phase SVOC transfer in indoor environment; iii) particles in the dynamic model improve the mass-transfer less efficiently than in the instantaneous equilibrium model, and the efficiency is determined by the gas/particle equilibrium partition coefficient (K_p). These results highlight the roles of airborne particles in indoor SVOC pollutants, and are expected to guide the design of experiments.