Lattice Boltzmann Simulations

Mixing is an important process in many practical applications such as chemical reactions, pollutant dispersion, diffusion in porous media, etc. Traditionally, mass and momentum transfer are modeled using the continuum assumption. However, as the Knudsen number Kn increases (characteristic hydrodynamic length becomes comparable to the mean free path of the gases), the continuum assumption breaks down and the use of a different approach is required. The LB method is appealing for simulating microflows, and its simple algorithm that can be easily modified for parallel computing. It seems, therefore, natural to extend the LB method to the simulation of mixtures and catalytic reactions in porous media. In the Combution Fundamentals Group at PSI, new models for the simulation of mixtures and chemical reactions within the LB frame are developed.

Fig. 1: Simulation of turbulent mixing in a binary mixture

Fig. 2: Mixing of a four component mixture (N₂, H₂, O₂, H₂O) in an opposed-jet configuration: velocity vector plot and H₂ mole fraction

Fig. 3: Catalytic reaction in a channel: CH4 + 2O2 -> CO2 + 2H2O. CO2 mole fraction