Investigation on the mechanism of convective heat and mass transfer with double diffusive effect inside a complex porous medium using lattice Boltzmann method

A new lattice Boltzmann model is proposed for the coupling of multi-physics in natural convection by introducing another distribution function to represent the scalar transport of mass and an additional source term on the right hand side of the lattice Boltzmann equation (LBE) based on the TD2G9 model. According to the Boussinesq assumption and considering the coupled diffusive effect, the governing equations for the coupling of multi-physics in natural convection is proposed based on the non-equilibrium thermodynamic theory. Combined with the algorithm for the reconstruction of a porous medium, this model is used to investigate the coupled heat and mass transfer under multi-physics of natural convection inside a porous medium at the pore scale. The characteristic of profiles of dimensionless velocity, temperature and concentration are shown graphically for different values of Rayleigh number (Ra) and porosity. Furthermore, the influence of the temperature gradient on the mass transfer inside a porous medium has been examined numerically. Thus, the mechanism of the coupled heat and mass transfer inside a porous medium is investigated numerically at the pore scale innovatively.