Treatment of transport at the interface between multilayers via the lattice boltzmann method

The lattice Boltzmann method (LBM) has reached maturity in many aspects for modeling incompressible, laminar flow and heat and mass transfer. However, many issues still need to be clarified. One of those is how to deal with Neumann boundary conditions (heat, momentum, and mass fluxes) at the interface between layers of different thermophysical properties, which is the topic of this work. In this work, we try to illustrate modeling of transient and steady-state heat transfer through multilayers, ensuring continuity of the flux, temperature, momentum, velocity, or species concentration at the interface, which is not a trivial issue in any of the numerical methods. Satisfying continuity conditions at the interface using the LBM needs special treatment, because the relaxation time depends on the thermophysical properties. In this work, methods to solve this issue are introduced for solving 1-D and 2-D, unsteady heat diffusion problems However, the methods can be equally applied for multilayer immiscible fluid flow and mass transfer problems. The predictions of the LBM are compared with those of the finite-volume method (FVM).