Lattice Boltzmann modeling of VOC desorption and diffusion in porous materials

This paper presents migration of volatile organic compounds (VOC) in porous building materials which are considered as stochastic porous media for the purpose of theoretical study. Desorption and diffusion processes of VOC in porous materials are simulated by three-dimensional lattice Boltzmann method (LBM) which is derived from binary mixture model. Based on this model, the simulated transient concentration distribution of binary gas diffusion in 3D channel which is obtained from simulation agrees well with analytical solution. The stochastic porous materials are constructed with quartet structure generation set (QSGS) method. This model can predict the effective diffusivity of porous materials successfully through comparing with empirical model and experimental data. A boundary condition of solid-pore interfaces is proposed to simulate desorption process of adsorption phase VOC on solid matrix. The coupling relationship between migration characteristics and key parameters of porous materials, such as partition coefficient, core distribution probability and porosity, is analyzed. The significance of desorption in migration process of VOC is observed.