Numerical simulations of surface reaction in porous media with lattice Boltzmann

Abstract

Numerical studies of two reactive porous structures are carried out, where fuel conversion is the main purpose. The flow is two-dimensional simulated by means of the lattice Boltzmann method. A diffusion-based Damköhler number is implicitly formulated in this work within a reactive boundary condition. A wall or surface global dimensionless factor η is introduced in the formulation to account for the lack of fuel conversion due to, e.g. flow leakage and model assumptions. Empirical relations and experimental results from a micro-power plant are used to calibrate and validate the present simulations. Grid and leakage sensitivity analysis are carried out. Good agreements with the empirical (Ergun) equations are shown in the numerical flow results. The flow trends in the experiments are replicated. The results from the simulated reactions follow the general trends seen in the experimental data. The present construction is capable to capture local variation of the flow velocities, reaction zone thickness and fuel concentration. The values of Péclet and two Damköhler numbers are in the same order as the empirical results, and are presented in conjunction with the factor η < 1 . This information is important to simulate surface reaction in porous media with lattice Boltzmann using realistic physical values.