Numerical investigation of dust sedimentation effects on wall adsorption of indoor SVOC by the immersed boundary-lattice Boltzmann method

Abstract

In this work the lattice Boltzmann method (LBM) is used to investigate semi-volatile organic compounds (SVOCs) mass transfer under the influence of particle sedimentation in the boundary-layer scale region. For the fluid-particle interaction, the direct-forcing immersed boundary (IB) method is applied to calculate the hydro-dynamic force. A mass-transfer IB method is employed to calculate the fluid-particle SVOC flux. Particles with zero and saturated initial-concentrations are studied to investigate the effects of clean and polluted particles. Effects of fluid/particle equilibrium coefficients, as well as particle diameters, are discussed. Wall adsorptions under the influence of multiple particles are also investigated. Numerical simulations reveal that a particle always intensifies wall adsorption independent of its initial SVOC concentration. The influences of particles on wall adsorption are associated with disturbance effect (disturbing air due to particle moving) and medium effect (SVOC mass transfer between particles and their surrounding air). Disturbance effect of clean particles overwhelms their medium effect while medium effect is dominant for saturated particles. Disturbance effect and medium effect both increase with particle diameter, and medium effect is more sensitive to particle diameter. Competitive adsorption occurs in presence of a number of particles and has an indirect impact on wall adsorption.