Simulation of solute dispersion in particle packs by the volume averaging method

The ability to predict solute dispersion behavior in homogeneous random particle packs by the volume averaging method is evaluated. Unit cells with periodic boundaries and random pore connectivity are numerically constructed. The asymptotic longitudinal and transverse dispersion coefficients are predicted by the volume averaging method in terms of these unit cells. The Peclet number is in the range of 0-1000. The Reynolds number is less than 1. Dispersion coefficients of eighteen unit cells with different sizes and pore geometries are compared. It is found that a significant scatter of dispersion coefficients exists when the size of the unit cell is small. The scatter decreases with increasing size of the unit cell. The predicted dispersion coefficients are compared with correlations obtained according to experimental and simulation results for homogeneous random particle packs and reasonable agreements are observed when the size of the unit cell is suitable.